What fractions do the shaded parts in each of the following figures represent?
Answer
(i) Total parts = 8
Shaded parts = 5
Fraction = Shaded parts Total parts \dfrac{\text{Shaded parts}}{\text{Total parts}} Total parts Shaded parts
= 5 8 \dfrac{5}{8} 8 5 .
Hence, fraction = 5 8 \dfrac{5}{8} 8 5 .
(ii) Total parts = 12
Shaded parts = 7
Fraction = Shaded parts Total parts \dfrac{\text{Shaded parts}}{\text{Total parts}} Total parts Shaded parts
= 7 12 \dfrac{7}{12} 12 7 .
Hence, fraction = 7 12 \dfrac{7}{12} 12 7 .
(iii) Total parts = 7
Shaded parts = 2
Fraction = Shaded parts Total parts \dfrac{\text{Shaded parts}}{\text{Total parts}} Total parts Shaded parts
= 2 7 \dfrac{2}{7} 7 2
Hence, fraction = 2 7 \dfrac{2}{7} 7 2 .
Write a fraction for each of the following :
(i) 4 parts out of 9 equal parts
(ii) 5 parts out of 11 equal parts
(iii) two-fifths
(iv) four-sevenths
(v) seven-tenths
(vi) six-eighths
Answer
(i) Total parts = 9
Given parts = 4
Fraction = Given parts Total parts \dfrac{\text{Given parts}}{\text{Total parts}} Total parts Given parts
= 4 9 \dfrac{4}{9} 9 4
Hence, fraction = 4 9 \dfrac{4}{9} 9 4 .
(ii) Total parts = 11
Given parts = 5
Fraction = Given parts Total parts \dfrac{\text{Given parts}}{\text{Total parts}} Total parts Given parts
= 5 11 \dfrac{5}{11} 11 5
Hence, fraction = 5 11 \dfrac{5}{11} 11 5 .
(iii) Total parts = 5
Given parts = 2
Fraction = Given parts Total parts \dfrac{\text{Given parts}}{\text{Total parts}} Total parts Given parts
= 2 5 \dfrac{2}{5} 5 2
Hence, fraction = 2 5 \dfrac{2}{5} 5 2 .
(iv) Total parts = 7
Given parts = 4
Fraction = Given parts Total parts \dfrac{\text{Given parts}}{\text{Total parts}} Total parts Given parts
= 4 7 \dfrac{4}{7} 7 4
Hence, fraction = 4 7 \dfrac{4}{7} 7 4 .
(v) Total parts = 10
Given parts = 7
Fraction = Given parts Total parts \dfrac{\text{Given parts}}{\text{Total parts}} Total parts Given parts
= 7 10 \dfrac{7}{10} 10 7
Hence, fraction = 7 10 \dfrac{7}{10} 10 7 .
(vi) Total parts = 8
Given parts = 6
Fraction = Given parts Total parts \dfrac{\text{Given parts}}{\text{Total parts}} Total parts Given parts
= 6 8 \dfrac{6}{8} 8 6
Hence, fraction = 6 8 \dfrac{6}{8} 8 6 .
Point out the numerator and denominator in each of the following fractions :
(i) 5 6 \dfrac{5}{6} 6 5
(ii) 3 7 \dfrac{3}{7} 7 3
(iii) 9 14 \dfrac{9}{14} 14 9
(iv) 1 20 \dfrac{1}{20} 20 1
(v) 12 25 \dfrac{12}{25} 25 12
Answer
(i) 5 6 \dfrac{5}{6} 6 5
Hence, numerator = 5 and denominator = 6.
(ii) 3 7 \dfrac{3}{7} 7 3
Hence, numerator = 3 and denominator = 7.
(iii) 9 14 \dfrac{9}{14} 14 9
Hence, numerator = 9 and denominator = 14.
(iv) 1 20 \dfrac{1}{20} 20 1
Hence, numerator = 1 and denominator = 20.
(v) 12 25 \dfrac{12}{25} 25 12
Hence, numerator = 12 and denominator = 25.
Write five fractions equivalent to each of the following :
(i) 2 3 \dfrac{2}{3} 3 2
(ii) 3 4 \dfrac{3}{4} 4 3
(iii) 5 6 \dfrac{5}{6} 6 5
(iv) 7 9 \dfrac{7}{9} 9 7
(v) 3 14 \dfrac{3}{14} 14 3
Answer
(i) 2 3 \dfrac{2}{3} 3 2
To find equivalent fractions, we multiply the numerator and denominator by a sequence of numbers (e.g., 2, 3, 4, 5, 6).
Multiply by 2: 2 × 2 3 × 2 = 4 6 \dfrac{2 \times 2}{3 \times 2} = \dfrac{4}{6} 3 × 2 2 × 2 = 6 4
Multiply by 3: 2 × 3 3 × 3 = 6 9 \dfrac{2 \times 3}{3 \times 3} = \dfrac{6}{9} 3 × 3 2 × 3 = 9 6
Multiply by 4: 2 × 4 3 × 4 = 8 12 \dfrac{2 \times 4}{3 \times 4} = \dfrac{8}{12} 3 × 4 2 × 4 = 12 8
Multiply by 5: 2 × 5 3 × 5 = 10 15 \dfrac{2 \times 5}{3 \times 5} = \dfrac{10}{15} 3 × 5 2 × 5 = 15 10
Multiply by 6: 2 × 6 3 × 6 = 12 18 \dfrac{2 \times 6}{3 \times 6} = \dfrac{12}{18} 3 × 6 2 × 6 = 18 12
Hence, the equivalent fractions are : 4 6 , 6 9 , 8 12 , 10 15 , 12 18 \dfrac{4}{6}, \dfrac{6}{9}, \dfrac{8}{12}, \dfrac{10}{15}, \dfrac{12}{18} 6 4 , 9 6 , 12 8 , 15 10 , 18 12 .
(ii) 3 4 \dfrac{3}{4} 4 3
To find equivalent fractions, we multiply the numerator and denominator by a sequence of numbers (e.g., 2, 3, 4, 5, 6).
Multiply by 2: 3 × 2 4 × 2 = 6 8 \dfrac{3 \times 2}{4 \times 2} = \dfrac{6}{8} 4 × 2 3 × 2 = 8 6
Multiply by 3: 3 × 3 4 × 3 = 9 12 \dfrac{3 \times 3}{4 \times 3} = \dfrac{9}{12} 4 × 3 3 × 3 = 12 9
Multiply by 4: 3 × 4 4 × 4 = 12 16 \dfrac{3 \times 4}{4 \times 4} = \dfrac{12}{16} 4 × 4 3 × 4 = 16 12
Multiply by 5: 3 × 5 4 × 5 = 15 20 \dfrac{3 \times 5}{4 \times 5} = \dfrac{15}{20} 4 × 5 3 × 5 = 20 15
Multiply by 6: 3 × 6 4 × 6 = 18 24 \dfrac{3 \times 6}{4 \times 6} = \dfrac{18}{24} 4 × 6 3 × 6 = 24 18
Hence, the equivalent fractions are: 6 8 , 9 12 , 12 16 , 15 20 , 18 24 \dfrac{6}{8}, \dfrac{9}{12}, \dfrac{12}{16}, \dfrac{15}{20}, \dfrac{18}{24} 8 6 , 12 9 , 16 12 , 20 15 , 24 18 .
(iii) 5 6 \dfrac{5}{6} 6 5
To find equivalent fractions, we multiply the numerator and denominator by a sequence of numbers (e.g., 2, 3, 4, 5, 6).
Multiply by 2: 5 × 2 6 × 2 = 10 12 \dfrac{5 \times 2}{6 \times 2} = \dfrac{10}{12} 6 × 2 5 × 2 = 12 10
Multiply by 3: 5 × 3 6 × 3 = 15 18 \dfrac{5 \times 3}{6 \times 3} = \dfrac{15}{18} 6 × 3 5 × 3 = 18 15
Multiply by 4: 5 × 4 6 × 4 = 20 24 \dfrac{5 \times 4}{6 \times 4} = \dfrac{20}{24} 6 × 4 5 × 4 = 24 20
Multiply by 5: 5 × 5 6 × 5 = 25 30 \dfrac{5 \times 5}{6 \times 5} = \dfrac{25}{30} 6 × 5 5 × 5 = 30 25
Multiply by 6: 5 × 6 6 × 6 = 30 36 \dfrac{5 \times 6}{6 \times 6} = \dfrac{30}{36} 6 × 6 5 × 6 = 36 30
Hence, the equivalent fractions are: 10 12 , 15 18 , 20 24 , 25 30 , 30 36 \dfrac{10}{12}, \dfrac{15}{18}, \dfrac{20}{24}, \dfrac{25}{30}, \dfrac{30}{36} 12 10 , 18 15 , 24 20 , 30 25 , 36 30 .
(iv) 7 9 \dfrac{7}{9} 9 7
To find equivalent fractions, we multiply the numerator and denominator by a sequence of numbers (e.g., 2, 3, 4, 5, 6).
Multiply by 2: 7 × 2 9 × 2 = 14 18 \dfrac{7 \times 2}{9 \times 2} = \dfrac{14}{18} 9 × 2 7 × 2 = 18 14
Multiply by 3: 7 × 3 9 × 3 = 21 27 \dfrac{7 \times 3}{9 \times 3} = \dfrac{21}{27} 9 × 3 7 × 3 = 27 21
Multiply by 4: 7 × 4 9 × 4 = 28 36 \dfrac{7 \times 4}{9 \times 4} = \dfrac{28}{36} 9 × 4 7 × 4 = 36 28
Multiply by 5: 7 × 5 9 × 5 = 35 45 \dfrac{7 \times 5}{9 \times 5} = \dfrac{35}{45} 9 × 5 7 × 5 = 45 35
Multiply by 6: 7 × 6 9 × 6 = 42 54 \dfrac{7 \times 6}{9 \times 6} = \dfrac{42}{54} 9 × 6 7 × 6 = 54 42
Hence, the equivalent fractions are: 14 18 , 21 27 , 28 36 , 35 45 , 42 54 \dfrac{14}{18}, \dfrac{21}{27}, \dfrac{28}{36}, \dfrac{35}{45}, \dfrac{42}{54} 18 14 , 27 21 , 36 28 , 45 35 , 54 42 .
(v) 3 14 \dfrac{3}{14} 14 3
To find equivalent fractions, we multiply the numerator and denominator by a sequence of numbers (e.g., 2, 3, 4, 5, 6).
Multiply by 2: 3 × 2 14 × 2 = 6 28 \dfrac{3 \times 2}{14 \times 2} = \dfrac{6}{28} 14 × 2 3 × 2 = 28 6
Multiply by 3: 3 × 3 14 × 3 = 9 42 \dfrac{3 \times 3}{14 \times 3} = \dfrac{9}{42} 14 × 3 3 × 3 = 42 9
Multiply by 4: 3 × 4 14 × 4 = 12 56 \dfrac{3 \times 4}{14 \times 4} = \dfrac{12}{56} 14 × 4 3 × 4 = 56 12
Multiply by 5: 3 × 5 14 × 5 = 15 70 \dfrac{3 \times 5}{14 \times 5} = \dfrac{15}{70} 14 × 5 3 × 5 = 70 15
Multiply by 6: 3 × 6 14 × 6 = 18 84 \dfrac{3 \times 6}{14 \times 6} = \dfrac{18}{84} 14 × 6 3 × 6 = 84 18
Hence, the equivalent fractions are: 6 28 , 9 42 , 12 56 , 15 70 , 18 84 \dfrac{6}{28}, \dfrac{9}{42}, \dfrac{12}{56}, \dfrac{15}{70}, \dfrac{18}{84} 28 6 , 42 9 , 56 12 , 70 15 , 84 18 .
Which of the following are the pairs of equivalent fractions?
(i) 4 5 \dfrac{4}{5} 5 4 and 24 30 \dfrac{24}{30} 30 24
(ii) 6 8 \dfrac{6}{8} 8 6 and 18 24 \dfrac{18}{24} 24 18
(iii) 9 16 \dfrac{9}{16} 16 9 and 3 4 \dfrac{3}{4} 4 3
(iv) 8 12 \dfrac{8}{12} 12 8 and 14 21 \dfrac{14}{21} 21 14
(v) 7 11 \dfrac{7}{11} 11 7 and 21 32 \dfrac{21}{32} 32 21
(vi) 5 12 \dfrac{5}{12} 12 5 and 35 84 \dfrac{35}{84} 84 35
Answer
(i) 4 5 \dfrac{4}{5} 5 4 and 24 30 \dfrac{24}{30} 30 24
By cross multiplication,
So, 4 x 30 = 120 and 5 x 24 = 120
Here, the cross products are equal.
Hence, 4 5 and 24 30 \dfrac{4}{5} \text{ and } \dfrac{24}{30} 5 4 and 30 24 are equivalent fractions.
(ii) 6 8 \dfrac{6}{8} 8 6 and 18 24 \dfrac{18}{24} 24 18
By cross multiplication,
So, 6 x 24 = 144 and 8 x 18 = 144
Here, the cross products are equal.
Hence, 6 8 and 18 24 \dfrac{6}{8}\text{ and } \dfrac{18}{24} 8 6 and 24 18 are equivalent fractions.
(iii) 9 16 \dfrac{9}{16} 16 9 and 3 4 \dfrac{3}{4} 4 3
By cross multiplication,
So, 9 x 4 = 36 and 16 x 3 = 48
Here, the cross products are not equal.
Hence, 9 16 and 3 4 \dfrac{9}{16}\text{ and } \dfrac{3}{4} 16 9 and 4 3 are not equivalent fractions.
(iv) 8 12 \dfrac{8}{12} 12 8 and 14 21 \dfrac{14}{21} 21 14
By cross multiplication,
So, 8 x 21 = 168 and 12 x 14 = 168
Here, the cross products are equal.
Hence, 8 12 and 14 21 \dfrac{8}{12}\text{ and } \dfrac{14}{21} 12 8 and 21 14 are equivalent fractions.
(v) 7 11 \dfrac{7}{11} 11 7 and 21 32 \dfrac{21}{32} 32 21
By cross multiplication,
So, 7 x 32 = 224 and 11 x 21 = 231
Here, the cross products are not equal.
Hence, 7 11 and 21 32 \dfrac{7}{11}\text{ and } \dfrac{21}{32} 11 7 and 32 21 are not equivalent fractions.
(vi) 5 12 \dfrac{5}{12} 12 5 and 35 84 \dfrac{35}{84} 84 35
By cross multiplication,
So, 5 x 84 = 420 and 12 x 35 = 420
Here, the cross products are equal.
Hence, 5 12 and 35 84 \dfrac{5}{12}\text{ and } \dfrac{35}{84} 12 5 and 84 35 are equivalent fractions.
Write an equivalent fraction of :
(i) 4 5 \dfrac{4}{5} 5 4 with numerator 32
(ii) 7 9 \dfrac{7}{9} 9 7 with numerator 42
(iii) 3 7 \dfrac{3}{7} 7 3 with denominator 63
(iv) 10 13 \dfrac{10}{13} 13 10 with denominator 78
Answer
(i) 4 5 \dfrac{4}{5} 5 4 with numerator 32
To find an equivalent fraction whose numerator is 32, we multiply the fraction 4 5 \dfrac{4}{5} 5 4 with 8,
4 5 = 4 × 8 5 × 8 = 32 40 \dfrac{4}{5} = \dfrac{4 \times 8}{5 \times 8} = \dfrac{32}{40} 5 4 = 5 × 8 4 × 8 = 40 32 .
Hence, an equivalent fraction of 4 5 = 32 40 \dfrac{4}{5} = \dfrac{32}{40} 5 4 = 40 32 .
(ii) 7 9 \dfrac{7}{9} 9 7 with numerator 42
To find an equivalent fraction whose numerator is 42, we multiply the fraction 7 9 \dfrac{7}{9} 9 7 with 6,
7 9 = 7 × 6 9 × 6 = 42 54 \dfrac{7}{9} = \dfrac{7 \times 6}{9 \times 6} = \dfrac{42}{54} 9 7 = 9 × 6 7 × 6 = 54 42 .
Hence, an equivalent fraction of 7 9 = 42 54 \dfrac{7}{9} = \dfrac{42}{54} 9 7 = 54 42 .
(iii) 3 7 \dfrac{3}{7} 7 3 with denominator 63
To find an equivalent fraction whose denominator is 63, we multiply the fraction 3 7 \dfrac{3}{7} 7 3 with 9,
3 7 = 3 × 9 7 × 9 = 27 63 \dfrac{3}{7} = \dfrac{3 \times 9}{7 \times 9} = \dfrac{27}{63} 7 3 = 7 × 9 3 × 9 = 63 27 .
Hence, an equivalent fraction of 3 7 = 27 63 \dfrac{3}{7} = \dfrac{27}{63} 7 3 = 63 27 .
(iv) 10 13 \dfrac{10}{13} 13 10 with denominator 78
To find an equivalent fraction whose denominator is 78, we multiply the fraction 10 13 \dfrac{10}{13} 13 10 with 6,
10 13 = 10 × 6 13 × 6 = 60 78 \dfrac{10}{13} = \dfrac{10 \times 6}{13 \times 6} = \dfrac{60}{78} 13 10 = 13 × 6 10 × 6 = 78 60 .
Hence, an equivalent fraction of 10 13 = 60 78 \dfrac{10}{13} = \dfrac{60}{78} 13 10 = 78 60 .
Write an equivalent fraction of :
(i) 32 48 \dfrac{32}{48} 48 32 with numerator 2
(ii) 21 28 \dfrac{21}{28} 28 21 with numerator 3
(iii) 24 56 \dfrac{24}{56} 56 24 with denominator 7
(iv) 121 132 \dfrac{121}{132} 132 121 with denominator 12
Answer
(i) 32 48 \dfrac{32}{48} 48 32 with numerator 2
The H.C.F. of 32 and 48 is 16. Thus,
To find an equivalent fraction whose numerator is 2, we divide the numerator and denominator of the given fraction by 16,
32 48 = 32 ÷ 16 48 ÷ 16 = 2 3 \dfrac{32}{48} = \dfrac{32 ÷ 16}{48 ÷ 16} = \dfrac{2}{3} 48 32 = 48 ÷ 16 32 ÷ 16 = 3 2 .
Hence, an equivalent fraction of 32 48 = 2 3 \dfrac{32}{48} = \dfrac{2}{3} 48 32 = 3 2 .
(ii) 21 28 \dfrac{21}{28} 28 21 with numerator 3
The H.C.F. of 21 and 28 is 7. Thus,
To find an equivalent fraction whose numerator is 3, we divide the numerator and denominator of the given fraction by 7,
21 28 = 21 ÷ 7 28 ÷ 7 = 3 4 \dfrac{21}{28} = \dfrac{21 ÷ 7}{28 ÷ 7} = \dfrac{3}{4} 28 21 = 28 ÷ 7 21 ÷ 7 = 4 3 .
Hence, an equivalent fraction of 21 28 = 3 4 \dfrac{21}{28} = \dfrac{3}{4} 28 21 = 4 3 .
(iii) 24 56 \dfrac{24}{56} 56 24 with denominator 7
The H.C.F. of 24 and 56 is 8. Thus,
To find an equivalent fraction whose denominator is 7, we divide the numerator and denominator of the given fraction by 8,
24 56 = 24 ÷ 8 56 ÷ 8 = 3 7 \dfrac{24}{56} = \dfrac{24 ÷ 8}{56 ÷ 8} = \dfrac{3}{7} 56 24 = 56 ÷ 8 24 ÷ 8 = 7 3 .
Hence, an equivalent fraction of 24 56 = 3 7 \dfrac{24}{56} = \dfrac{3}{7} 56 24 = 7 3 .
(iv) 121 132 \dfrac{121}{132} 132 121 with denominator 12
The H.C.F. of 121 and 132 is 11. Thus,
To find an equivalent fraction whose denominator is 12, we divide the numerator and denominator of the given fraction by 11,
121 132 = 121 ÷ 11 132 ÷ 11 = 11 12 \dfrac{121}{132} = \dfrac{121 ÷ 11}{132 ÷ 11} = \dfrac{11}{12} 132 121 = 132 ÷ 11 121 ÷ 11 = 12 11 .
Hence, an equivalent fraction of 121 132 = 11 12 \dfrac{121}{132} = \dfrac{11}{12} 132 121 = 12 11 .
Write an equivalent fraction of :
(i) 45 54 \dfrac{45}{54} 54 45 with numerator 20.
(ii) 75 90 \dfrac{75}{90} 90 75 with denominator 42.
Answer
(i) 45 54 \dfrac{45}{54} 54 45 with numerator 20.
The H.C.F. of 45 and 54 is 9. Thus,
To find an equivalent fraction whose numerator is 20,
We divide the numerator and denominator of the given fraction by 9,
45 54 = 45 ÷ 9 54 ÷ 9 = 5 6 \dfrac{45}{54} = \dfrac{45 ÷ 9}{54 ÷ 9} = \dfrac{5}{6} 54 45 = 54 ÷ 9 45 ÷ 9 = 6 5 .
Now, to get a fraction with numerator 20, we multiply both the numerator and denominator by 4,
5 6 = 5 × 4 6 × 4 = 20 24 \dfrac{5}{6} = \dfrac{5 \times 4}{6 \times 4} = \dfrac{20}{24} 6 5 = 6 × 4 5 × 4 = 24 20 .
Hence, the equivalent fraction = 20 24 \dfrac{20}{24} 24 20 .
(ii) 75 90 \dfrac{75}{90} 90 75 with denominator 42.
The H.C.F. of 75 and 90 is 15. Thus,
To find an equivalent fraction whose denominator is 42,
We divide the numerator and denominator of the given fraction by 15,
75 90 = 75 ÷ 15 90 ÷ 15 = 5 6 \dfrac{75}{90} = \dfrac{75 ÷ 15}{90 ÷ 15} = \dfrac{5}{6} 90 75 = 90 ÷ 15 75 ÷ 15 = 6 5 .
Now, to get a fraction with denominator 42, we multiply both the numerator and denominator by 7,
5 6 = 5 × 7 6 × 7 = 35 42 \dfrac{5}{6} = \dfrac{5 \times 7}{6 \times 7} = \dfrac{35}{42} 6 5 = 6 × 7 5 × 7 = 42 35 .
Hence, the equivalent fraction = 35 42 \dfrac{35}{42} 42 35 .
Write the missing numerals in the place-holders :
(i) 4 9 \dfrac{4}{9} 9 4 = 63 63 \dfrac{\boxed{\phantom{63}}}{63} 63 63
(ii) 3 4 \dfrac{3}{4} 4 3 = 18 63 \dfrac{18}{\boxed{\phantom{63}}} 63 18
(iii) 42 70 \dfrac{42}{70} 70 42 = 3 63 \dfrac{3}{\boxed{\phantom{63}}} 63 3
(iv) 52 78 \dfrac{52}{78} 78 52 = 63 6 \dfrac{\boxed{\phantom{63}}}{6} 6 63
Answer
(i) 4 9 \dfrac{4}{9} 9 4 = 63 63 \dfrac{\boxed{\phantom{63}}}{63} 63 63
4 9 = 4 × 7 9 × 7 = 28 63 \dfrac{4}{9} = \dfrac{4 \times 7}{9 \times 7} = \dfrac{28}{63} 9 4 = 9 × 7 4 × 7 = 63 28
Hence, 4 9 \dfrac{4}{9} 9 4 = 28 63 \dfrac{\boxed{28}}{63} 63 28 .
(ii) 3 4 \dfrac{3}{4} 4 3 = 18 63 \dfrac{18}{\boxed{\phantom{63}}} 63 18
3 4 = 3 × 6 4 × 6 = 18 24 \dfrac{3}{4} = \dfrac{3 \times 6}{4 \times 6} = \dfrac{18}{24} 4 3 = 4 × 6 3 × 6 = 24 18
Hence, 3 4 \dfrac{3}{4} 4 3 = 18 24 \dfrac{18}{\boxed{24}} 24 18 .
(iii) 42 70 \dfrac{42}{70} 70 42 = 3 63 \dfrac{3}{\boxed{\phantom{63}}} 63 3
Simplifying the fraction,
42 70 = 42 ÷ 14 70 ÷ 14 = 3 5 \dfrac{42}{70} = \dfrac{42 ÷ 14}{70 ÷ 14} = \dfrac{3}{5} 70 42 = 70 ÷ 14 42 ÷ 14 = 5 3
Hence, 42 70 \dfrac{42}{70} 70 42 = 3 5 \dfrac{3}{\boxed{5}} 5 3 .
(iv) 52 78 \dfrac{52}{78} 78 52 = 63 6 \dfrac{\boxed{\phantom{63}}}{6} 6 63
Simplifying the fraction,
52 78 = 52 ÷ 13 78 ÷ 13 = 4 6 \dfrac{52}{78} = \dfrac{52 ÷ 13}{78 ÷ 13} = \dfrac{4}{6} 78 52 = 78 ÷ 13 52 ÷ 13 = 6 4
Hence, 52 78 \dfrac{52}{78} 78 52 = 4 6 \dfrac{\boxed{4}}{6} 6 4 .
What fraction of an hour is 25 minutes?
Answer
Given minutes = 25 minutes
Total minutes = 60 minutes
Fraction = Given minutes Total minutes = 25 60 \dfrac{\text{Given minutes}}{\text{Total minutes}} = \dfrac{25}{60} Total minutes Given minutes = 60 25 .
Hence, required fraction = 25 60 \dfrac{25}{60} 60 25 .
What fraction of a day is 9 hours?
Answer
Given hours = 9 hours
Total hours = 24 hours
Fraction = Given hours Total hours = 9 24 \dfrac{\text{Given hours}}{\text{Total hours}} = \dfrac{9}{24} Total hours Given hours = 24 9 .
Hence, required fraction = 9 24 \dfrac{9}{24} 24 9 .
Which of the following fractions are in simplest form?
(i) 21 40 \dfrac{21}{40} 40 21
(ii) 35 49 \dfrac{35}{49} 49 35
(iii) 42 54 \dfrac{42}{54} 54 42
(iv) 64 81 \dfrac{64}{81} 81 64
(v) 56 65 \dfrac{56}{65} 65 56
(vi) 23 92 \dfrac{23}{92} 92 23
(vii) 102 119 \dfrac{102}{119} 119 102
(viii) 91 114 \dfrac{91}{114} 114 91
Answer
A fraction is in its simplest form when the highest common factor (HCF) of its numerator and denominator is 1.
(i) 21 40 \dfrac{21}{40} 40 21
First, we find the H.C.F. of 21 and 40.
21 ) 40 ( ‾ 1 a c ) ) − 21 ‾ x 2 = ) 19 ) 21 ( ‾ 1 a c = s c ) ) − 19 ‾ x 2 ) + 2 x = 2 ) 19 ( ‾ 9 a c = s c + s a ) ) − 18 ‾ x 2 ) + 2 x = + d c a 1 ) 2 ( ‾ 2 a c = s c + s a + s a ) ) − 2 ‾ x 2 + 3 x − 54 ) + 2 x ) × \begin{array}{l} 21\overline{\smash{\big)}\quad 40\smash{\big(}} 1 \\ \phantom{ac)}\phantom{)}\underline{-21} \\ \phantom{{x^2 =)}} 19 \overline{\smash{\big)}\quad 21\smash{\big(}} 1 \\ \phantom{ac = sc)}\phantom{)}\underline{-19} \\ \phantom{{x^2 )} + 2x =}2\overline{\smash{\big)}\quad 19 \smash{\big(}} 9 \\ \phantom{ac = sc + sa)}\phantom{)}\underline{-18} \\ \phantom{{x^2 )} + 2x = + dca}1\overline{\smash{\big)}\quad 2 \smash{\big(}} 2 \\ \phantom{ac = sc + sa + sa)}\phantom{)}\underline{-2} \\ \phantom{{x^2 + 3x - 54)} + 2x)}\times \\ \end{array} 21 ) 40 ( 1 a c )) − 21 x 2 = ) 19 ) 21 ( 1 a c = sc )) − 19 x 2 ) + 2 x = 2 ) 19 ( 9 a c = sc + s a )) − 18 x 2 ) + 2 x = + d c a 1 ) 2 ( 2 a c = sc + s a + s a )) − 2 x 2 + 3 x − 54 ) + 2 x ) ×
So, HCF of 21 and 40 = 1.
Hence, 21 40 \dfrac{21}{40} 40 21 is in simplest form.
(ii) 35 49 \dfrac{35}{49} 49 35
35 ) 49 ( ‾ 1 a c ) ) − 35 ‾ x 2 = ) 14 ) 35 ( ‾ 2 a c = s c ) ) − 28 ‾ x 2 ) + 2 x = 7 ) 14 ( ‾ 2 a c = s c + s a ) ) − 14 ‾ x 2 + 3 x − 54 ) + × \begin{array}{l} 35\overline{\smash{\big)}\quad 49\smash{\big(}} 1 \\ \phantom{ac)}\phantom{)}\underline{-35} \\ \phantom{{x^2 =)}} 14 \overline{\smash{\big)}\quad 35\smash{\big(}} 2 \\ \phantom{ac = sc)}\phantom{)}\underline{-28} \\ \phantom{{x^2 )} + 2x =}7\overline{\smash{\big)}\quad 14 \smash{\big(}} 2 \\ \phantom{ac = sc + sa)}\phantom{)}\underline{-14} \\ \phantom{{x^2 + 3x - 54)} + }\times \\ \end{array} 35 ) 49 ( 1 a c )) − 35 x 2 = ) 14 ) 35 ( 2 a c = sc )) − 28 x 2 ) + 2 x = 7 ) 14 ( 2 a c = sc + s a )) − 14 x 2 + 3 x − 54 ) + ×
So, HCF of 35 and 49 = 7.
Hence, 35 49 \dfrac{35}{49} 49 35 is not in simplest form.
(iii) 42 54 \dfrac{42}{54} 54 42
42 ) 54 ( ‾ 1 a c ) ) − 42 ‾ x 2 = ) 12 ) 42 ( ‾ 3 a c = s c ) ) ) − 36 ‾ x 2 ) + 2 x = 6 ) 12 ( ‾ 2 a c = s c + s a ) ) − 12 ‾ x 2 + 3 x − 54 ) + × \begin{array}{l} 42\overline{\smash{\big)}\quad 54\smash{\big(}} 1 \\ \phantom{ac)}\phantom{)}\underline{-42} \\ \phantom{{x^2 =)}} 12 \overline{\smash{\big)}\quad 42\smash{\big(}} 3 \\ \phantom{ac = sc))}\phantom{)}\underline{-36} \\ \phantom{{x^2 )} + 2x =}6\overline{\smash{\big)}\quad 12 \smash{\big(}} 2 \\ \phantom{ac = sc + sa)}\phantom{)}\underline{-12} \\ \phantom{{x^2 + 3x - 54)} + }\times \\ \end{array} 42 ) 54 ( 1 a c )) − 42 x 2 = ) 12 ) 42 ( 3 a c = sc ))) − 36 x 2 ) + 2 x = 6 ) 12 ( 2 a c = sc + s a )) − 12 x 2 + 3 x − 54 ) + ×
So, HCF of 42 and 54 = 6.
Hence, 42 54 \dfrac{42}{54} 54 42 is not in simplest form.
(iv) 64 81 \dfrac{64}{81} 81 64
64 ) 81 ( ‾ 1 a c ) ) − 64 ‾ x 2 = ) 17 ) 64 ( ‾ 3 a c = s c ) ) ) − 51 ‾ x 2 ) + 2 x = 13 ) 17 ( ‾ 1 a c = s c + s a ) ) ) ) − 13 ‾ x 2 ) + 2 x = a c d v u 4 ) 13 ( ‾ 3 a c = s c + s a + d f ) ) − 12 ‾ x 2 ) + 2 x = a c d v + d f 1 ) 4 ( ‾ 4 a c = s c + s a + d f + d c ) ) − 4 ‾ x 2 + 3 x − 54 ) + a d v n s c j × \begin{array}{l} 64\overline{\smash{\big)}\quad 81\smash{\big(}} 1 \\ \phantom{ac)}\phantom{)}\underline{-64} \\ \phantom{{x^2 =)}} 17 \overline{\smash{\big)}\quad 64\smash{\big(}} 3 \\ \phantom{ac = sc))}\phantom{)}\underline{-51} \\ \phantom{{x^2 )} + 2x =}13\overline{\smash{\big)}\quad 17 \smash{\big(}} 1 \\ \phantom{ac = sc + sa)))}\phantom{)}\underline{-13} \\ \phantom{{x^2 )} + 2x = acdvu}4\overline{\smash{\big)}\quad 13 \smash{\big(}} 3 \\ \phantom{ac = sc + sa+ df)}\phantom{)}\underline{-12} \\ \phantom{{x^2 )} + 2x = acdv + df}1\overline{\smash{\big)}\quad 4 \smash{\big(}} 4 \\ \phantom{ac = sc + sa+ df + dc)}\phantom{)}\underline{-4} \\ \phantom{{x^2 + 3x - 54)} + advnscj }\times \\ \end{array} 64 ) 81 ( 1 a c )) − 64 x 2 = ) 17 ) 64 ( 3 a c = sc ))) − 51 x 2 ) + 2 x = 13 ) 17 ( 1 a c = sc + s a )))) − 13 x 2 ) + 2 x = a c d vu 4 ) 13 ( 3 a c = sc + s a + df )) − 12 x 2 ) + 2 x = a c d v + df 1 ) 4 ( 4 a c = sc + s a + df + d c )) − 4 x 2 + 3 x − 54 ) + a d v n sc j ×
So, HCF of 64 and 81 = 1.
Hence, 64 81 \dfrac{64}{81} 81 64 is in simplest form.
(v) 56 65 \dfrac{56}{65} 65 56
56 ) 65 ( ‾ 1 a c ) ) − 56 ‾ x 2 = ) 9 ) 56 ( ‾ 6 a c = s c ) ) − 54 ‾ x 2 ) + 2 x = 2 ) 9 ( ‾ 4 a c = s c + s a ) ) ) − 8 ‾ x 2 ) + 2 x = a c d v 1 ) 2 ( ‾ 2 a c = s c + s a + d f ) ) − 2 ‾ x 2 + 3 x − 54 ) + a a x × \begin{array}{l} 56\overline{\smash{\big)}\quad 65\smash{\big(}} 1 \\ \phantom{ac)}\phantom{)}\underline{-56} \\ \phantom{{x^2 =)}} 9 \overline{\smash{\big)}\quad 56\smash{\big(}} 6 \\ \phantom{ac = sc)}\phantom{)}\underline{-54} \\ \phantom{{x^2 )} + 2x =}2\overline{\smash{\big)}\quad 9 \smash{\big(}} 4 \\ \phantom{ac = sc + sa))}\phantom{)}\underline{-8} \\ \phantom{{x^2 )} + 2x = acdv}1\overline{\smash{\big)}\quad 2 \smash{\big(}} 2 \\ \phantom{ac = sc + sa+ df)}\phantom{)}\underline{-2} \\ \phantom{{x^2 + 3x - 54)} + aax}\times \\ \end{array} 56 ) 65 ( 1 a c )) − 56 x 2 = ) 9 ) 56 ( 6 a c = sc )) − 54 x 2 ) + 2 x = 2 ) 9 ( 4 a c = sc + s a ))) − 8 x 2 ) + 2 x = a c d v 1 ) 2 ( 2 a c = sc + s a + df )) − 2 x 2 + 3 x − 54 ) + aa x ×
So, HCF of 56 and 65 = 1.
Hence, 56 65 \dfrac{56}{65} 65 56 is in simplest form.
(vi) 23 92 \dfrac{23}{92} 92 23
23 ) 92 ( ‾ 4 a c ) ) − 92 ‾ x 2 + 3 × \begin{array}{l} 23\overline{\smash{\big)}\quad 92\smash{\big(}} 4 \\ \phantom{ac)}\phantom{)}\underline{-92} \\ \phantom{{x^2 + 3}}\times \\ \end{array} 23 ) 92 ( 4 a c )) − 92 x 2 + 3 ×
So, HCF of 23 and 92 = 23.
Hence, 23 92 \dfrac{23}{92} 92 23 is not in simplest form.
(vii) 102 119 \dfrac{102}{119} 119 102
102 ) 119 ( ‾ 1 a c = ) − 102 ‾ x 2 = a a ) 17 ) 102 ( ‾ 6 a c = s c = s ) ) − 102 ‾ x 2 + 3 x − 54 ) x × \begin{array}{l} 102\overline{\smash{\big)}\quad 119\smash{\big(}} 1 \\ \phantom{ac =)}\phantom{}\underline{-102} \\ \phantom{{x^2 = aa)}} 17 \overline{\smash{\big)}\quad 102\smash{\big(}} 6 \\ \phantom{ac = sc =s)}\phantom{)}\underline{-102} \\ \phantom{{x^2 + 3x - 54)} x}\times \\ \end{array} 102 ) 119 ( 1 a c = ) − 102 x 2 = aa ) 17 ) 102 ( 6 a c = sc = s )) − 102 x 2 + 3 x − 54 ) x ×
So, HCF of 102 and 119 = 17.
Hence, 102 119 \dfrac{102}{119} 119 102 is not in simplest form.
(viii) 91 114 \dfrac{91}{114} 114 91
91 ) 114 ( ‾ 1 a c + ) ) − 91 ‾ x 2 = ) ) ) 23 ) 91 ( ‾ 3 a c = s c ) ) ) − 69 ‾ x 2 ) + 2 x = 22 ) 23 ( ‾ 1 a c = s c + s a = ) ) − 22 ‾ x 2 ) + 2 x = a c + a d 1 ) 22 ( ‾ 22 a c = s c + s a + d f − ) ) − 22 ‾ x 2 + 3 x − 54 ) + a a x + s × \begin{array}{l} 91\overline{\smash{\big)}\quad 114\smash{\big(}} 1 \\ \phantom{ac +)}\phantom{)}\underline{-91} \\ \phantom{{x^2 =)))}} 23 \overline{\smash{\big)}\quad 91\smash{\big(}} 3 \\ \phantom{ac = sc))}\phantom{)}\underline{-69} \\ \phantom{{x^2 )} + 2x =}22\overline{\smash{\big)}\quad 23 \smash{\big(}} 1 \\ \phantom{ac = sc + sa =)}\phantom{)}\underline{-22} \\ \phantom{{x^2 )} + 2x = ac + ad}1\overline{\smash{\big)}\quad 22 \smash{\big(}} 22 \\ \phantom{ac = sc + sa+ df -)}\phantom{)}\underline{-22} \\ \phantom{{x^2 + 3x - 54)} + aax+ s} \times \\ \end{array} 91 ) 114 ( 1 a c + )) − 91 x 2 = ))) 23 ) 91 ( 3 a c = sc ))) − 69 x 2 ) + 2 x = 22 ) 23 ( 1 a c = sc + s a = )) − 22 x 2 ) + 2 x = a c + a d 1 ) 22 ( 22 a c = sc + s a + df − )) − 22 x 2 + 3 x − 54 ) + aa x + s ×
So, HCF of 91 and 114 = 1.
Hence, 91 114 \dfrac{91}{114} 114 91 is in simplest form.
Reduce each of the following fraction to its lowest terms :
(i) 27 36 \dfrac{27}{36} 36 27
(ii) 45 54 \dfrac{45}{54} 54 45
(iii) 38 95 \dfrac{38}{95} 95 38
(iv) 58 87 \dfrac{58}{87} 87 58
(v) 85 153 \dfrac{85}{153} 153 85
(vi) 105 168 \dfrac{105}{168} 168 105
(vii) 117 143 \dfrac{117}{143} 143 117
(viii) 135 150 \dfrac{135}{150} 150 135
Answer
(i) Prime factorizing,
27 36 = 3 × 3 × 3 2 × 2 × 3 × 3 = 3 4 \dfrac{27}{36} = \dfrac{3 \times 3 \times 3}{2 \times 2 \times 3 \times 3} = \dfrac{3}{4} 36 27 = 2 × 2 × 3 × 3 3 × 3 × 3 = 4 3 .
Hence, 27 36 \dfrac{27}{36} 36 27 in lowest terms is 3 4 \dfrac{3}{4} 4 3 .
(ii) Prime factorizing,
45 54 = 3 × 3 × 5 3 × 3 × 3 × 2 = 5 6 \dfrac{45}{54} = \dfrac{3 \times 3 \times 5}{3 \times 3 \times 3 \times 2} = \dfrac{5}{6} 54 45 = 3 × 3 × 3 × 2 3 × 3 × 5 = 6 5 .
Hence, 45 54 \dfrac{45}{54} 54 45 in lowest terms is 5 6 \dfrac{5}{6} 6 5 .
(iii) Prime factorizing,
38 95 = 2 × 19 5 × 19 = 2 5 \dfrac{38}{95} = \dfrac{2 \times 19}{5 \times 19} = \dfrac{2}{5} 95 38 = 5 × 19 2 × 19 = 5 2 .
Hence, 38 95 \dfrac{38}{95} 95 38 in lowest terms is 2 5 \dfrac{2}{5} 5 2 .
(iv) Prime factorizing,
58 87 = 2 × 29 3 × 29 = 2 3 \dfrac{58}{87} = \dfrac{2 \times 29}{3 \times 29} = \dfrac{2}{3} 87 58 = 3 × 29 2 × 29 = 3 2 .
Hence, 58 87 \dfrac{58}{87} 87 58 in lowest terms is 2 3 \dfrac{2}{3} 3 2 .
(v) Prime factorizing,
85 153 = 5 × 17 3 × 3 × 17 = 5 9 \dfrac{85}{153} = \dfrac{5 \times 17}{3 \times 3 \times 17} = \dfrac{5}{9} 153 85 = 3 × 3 × 17 5 × 17 = 9 5 .
Hence, 85 153 \dfrac{85}{153} 153 85 in lowest terms is 5 9 \dfrac{5}{9} 9 5 .
(vi) Prime factorizing,
105 168 = 3 × 5 × 7 2 × 2 × 2 × 3 × 7 = 5 8 \dfrac{105}{168} = \dfrac{3 \times 5 \times 7}{2 \times 2 \times 2\times 3 \times 7} = \dfrac{5}{8} 168 105 = 2 × 2 × 2 × 3 × 7 3 × 5 × 7 = 8 5 .
Hence, 105 168 \dfrac{105}{168} 168 105 in lowest terms is 5 8 \dfrac{5}{8} 8 5 .
(vii) Prime factorizing,
117 143 = 3 × 3 × 13 11 × 13 = 9 11 \dfrac{117}{143} = \dfrac{3 \times 3 \times 13}{11 \times 13} = \dfrac{9}{11} 143 117 = 11 × 13 3 × 3 × 13 = 11 9 .
Hence, 117 143 \dfrac{117}{143} 143 117 in lowest terms is 9 11 \dfrac{9}{11} 11 9 .
(viii) Prime factorizing,
135 150 = 3 × 3 × 3 × 5 2 × 3 × 5 × 5 = 9 10 \dfrac{135}{150} = \dfrac{3 \times 3 \times 3 \times 5}{2 \times 3 \times 5 \times 5} = \dfrac{9}{10} 150 135 = 2 × 3 × 5 × 5 3 × 3 × 3 × 5 = 10 9 .
Hence, 135 150 \dfrac{135}{150} 150 135 in lowest terms is 9 10 \dfrac{9}{10} 10 9 .
Point out the proper and improper fractions from the following :
(i) 7 9 \dfrac{7}{9} 9 7
(ii) 16 11 \dfrac{16}{11} 11 16
(iii) 18 25 \dfrac{18}{25} 25 18
(iv) 10 10 \dfrac{10}{10} 10 10
(v) 37 23 \dfrac{37}{23} 23 37
(vi) 21 8 \dfrac{21}{8} 8 21
(vii) 56 57 \dfrac{56}{57} 57 56
(viii) 137 105 \dfrac{137}{105} 105 137
(ix) 2 1 \dfrac{2}{1} 1 2
(x) 100 101 \dfrac{100}{101} 101 100
Answer
(i) 7 9 \dfrac{7}{9} 9 7
A proper fraction is a fraction where the numerator (the top number) is less than the denominator (the bottom number).
Here, 7 < 9
Hence, 7 9 \dfrac{7}{9} 9 7 is a proper fraction.
(ii) 16 11 \dfrac{16}{11} 11 16
An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Here, 16 > 11
Hence, 16 11 \dfrac{16}{11} 11 16 is an improper fraction.
(iii) 18 25 \dfrac{18}{25} 25 18
A proper fraction is a fraction where the numerator (the top number) is less than the denominator (the bottom number).
Here, 18 < 25
Hence, 18 25 \dfrac{18}{25} 25 18 is a proper fraction.
(iv) 10 10 \dfrac{10}{10} 10 10
An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Here, 10 = 10
Hence, 10 10 \dfrac{10}{10} 10 10 is an improper fraction.
(v) 37 23 \dfrac{37}{23} 23 37
An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Here, 37 > 23
Hence, 37 23 \dfrac{37}{23} 23 37 is an improper fraction.
(vi) 21 8 \dfrac{21}{8} 8 21
An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Here, 21 > 8
Hence, 21 8 \dfrac{21}{8} 8 21 is an improper fraction.
(vii) 56 57 \dfrac{56}{57} 57 56
A proper fraction is a fraction where the numerator (the top number) is less than the denominator (the bottom number).
Here, 56 < 57
Hence, 56 57 \dfrac{56}{57} 57 56 is a proper fraction.
(viii) 137 105 \dfrac{137}{105} 105 137
An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Here, 137 > 105
Hence, 137 105 \dfrac{137}{105} 105 137 is an improper fraction.
(ix) 2 1 \dfrac{2}{1} 1 2
An improper fraction is a fraction where the numerator is greater than or equal to the denominator.
Here, 2 > 1
Hence, 2 1 \dfrac{2}{1} 1 2 is an improper fraction.
(x) 100 101 \dfrac{100}{101} 101 100
A proper fraction is a fraction where the numerator (the top number) is less than the denominator (the bottom number).
Here, 100 < 101
Hence, 100 101 \dfrac{100}{101} 101 100 is a proper fraction.
Convert each of the following mixed fractions into an improper fraction :
(i) 8 3 4 8\dfrac{3}{4} 8 4 3
(ii) 5 11 13 5\dfrac{11}{13} 5 13 11
(iii) 10 7 9 10\dfrac{7}{9} 10 9 7
(iv) 33 1 3 33\dfrac{1}{3} 33 3 1
(v) 9 7 16 9\dfrac{7}{16} 9 16 7
Answer
(i) 8 3 4 8\dfrac{3}{4} 8 4 3
8 3 4 = 8 × 4 + 3 4 = 35 4 8\dfrac{3}{4} = \dfrac{8 \times 4 + 3}{4} = \dfrac{35}{4} 8 4 3 = 4 8 × 4 + 3 = 4 35
Hence, the improper fraction = 35 4 \dfrac{35}{4} 4 35 .
(ii) 5 11 13 5\dfrac{11}{13} 5 13 11
5 11 13 = 5 × 13 + 11 13 = 76 13 5\dfrac{11}{13} = \dfrac{5 \times 13 + 11}{13} = \dfrac{76}{13} 5 13 11 = 13 5 × 13 + 11 = 13 76
Hence, the improper fraction = 76 13 \dfrac{76}{13} 13 76 .
(iii) 10 7 9 10\dfrac{7}{9} 10 9 7
10 7 9 = 10 × 9 + 7 9 = 97 9 10\dfrac{7}{9} = \dfrac{10 \times 9 + 7}{9} = \dfrac{97}{9} 10 9 7 = 9 10 × 9 + 7 = 9 97
Hence, the improper fraction = 97 9 \dfrac{97}{9} 9 97 .
(iv) 33 1 3 33\dfrac{1}{3} 33 3 1
33 1 3 = 33 × 3 + 1 3 = 100 3 33\dfrac{1}{3} = \dfrac{33 \times 3 + 1}{3} = \dfrac{100}{3} 33 3 1 = 3 33 × 3 + 1 = 3 100
Hence, the improper fraction = 100 3 \dfrac{100}{3} 3 100 .
(v) 9 7 16 9\dfrac{7}{16} 9 16 7
9 7 16 = 9 × 16 + 7 16 = 151 16 9\dfrac{7}{16} = \dfrac{9 \times 16 + 7}{16} = \dfrac{151}{16} 9 16 7 = 16 9 × 16 + 7 = 16 151
Hence, the improper fraction = 151 16 \dfrac{151}{16} 16 151 .
Convert each of the following improper fractions into a mixed fraction :
(i) 31 5 \dfrac{31}{5} 5 31
(ii) 80 7 \dfrac{80}{7} 7 80
(iii) 107 3 \dfrac{107}{3} 3 107
(iv) 115 13 \dfrac{115}{13} 13 115
(v) 200 9 \dfrac{200}{9} 9 200
Answer
(i) 31 5 \dfrac{31}{5} 5 31
On dividing 31 by 5, we get quotient = 6 and remainder = 1.
∴ 31 5 = 6 + 1 5 = 6 1 5 \therefore \dfrac{31}{5} = 6 + \dfrac{1}{5} = 6\dfrac{1}{5} ∴ 5 31 = 6 + 5 1 = 6 5 1 .
Hence, the mixed fraction is 6 1 5 6\dfrac{1}{5} 6 5 1 .
(ii) 80 7 \dfrac{80}{7} 7 80
On dividing 80 by 7, we get quotient = 11 and remainder = 3.
∴ 80 7 = 11 + 3 7 = 11 3 7 \therefore \dfrac{80}{7} = 11 + \dfrac{3}{7} = 11\dfrac{3}{7} ∴ 7 80 = 11 + 7 3 = 11 7 3 .
Hence, the mixed fraction is 11 3 7 11\dfrac{3}{7} 11 7 3 .
(iii) 107 3 \dfrac{107}{3} 3 107
On dividing 107 by 3, we get quotient = 35 and remainder = 2.
∴ 107 3 = 35 + 2 3 = 35 2 3 \therefore \dfrac{107}{3} = 35 + \dfrac{2}{3} = 35\dfrac{2}{3} ∴ 3 107 = 35 + 3 2 = 35 3 2 .
Hence, the mixed fraction is 35 2 3 35\dfrac{2}{3} 35 3 2 .
(iv) 115 13 \dfrac{115}{13} 13 115
On dividing 115 by 13, we get quotient = 8 and remainder = 11.
∴ 115 13 = 8 + 11 13 = 8 11 13 \therefore \dfrac{115}{13} = 8 + \dfrac{11}{13} = 8\dfrac{11}{13} ∴ 13 115 = 8 + 13 11 = 8 13 11 .
Hence, the mixed fraction is 8 11 13 8\dfrac{11}{13} 8 13 11 .
(v) 200 9 \dfrac{200}{9} 9 200
On dividing 200 by 9, we get quotient = 22 and remainder = 2.
∴ 200 9 = 22 + 2 9 = 22 2 9 . \therefore \dfrac{200}{9} = 22 + \dfrac{2}{9} = 22\dfrac{2}{9}. ∴ 9 200 = 22 + 9 2 = 22 9 2 .
Hence, the mixed fraction is 22 2 9 22\dfrac{2}{9} 22 9 2 .
Convert each of the following sets of unlike fractions into that of like fractions :
(i) 4 5 , 7 10 , 11 15 , 13 20 \dfrac{4}{5}, \dfrac{7}{10}, \dfrac{11}{15}, \dfrac{13}{20} 5 4 , 10 7 , 15 11 , 20 13
(ii) 2 3 , 1 4 , 5 6 , 7 8 , 11 12 \dfrac{2}{3}, \dfrac{1}{4}, \dfrac{5}{6}, \dfrac{7}{8}, \dfrac{11}{12} 3 2 , 4 1 , 6 5 , 8 7 , 12 11
(iii) 1 3 , 3 4 , 5 12 , 9 16 , 17 24 \dfrac{1}{3}, \dfrac{3}{4}, \dfrac{5}{12}, \dfrac{9}{16}, \dfrac{17}{24} 3 1 , 4 3 , 12 5 , 16 9 , 24 17
(iv) 2 3 , 1 6 , 5 9 , 7 12 , 13 18 \dfrac{2}{3}, \dfrac{1}{6}, \dfrac{5}{9}, \dfrac{7}{12}, \dfrac{13}{18} 3 2 , 6 1 , 9 5 , 12 7 , 18 13
(v) 1 2 , 4 7 , 9 14 , 11 21 , 37 42 \dfrac{1}{2}, \dfrac{4}{7}, \dfrac{9}{14}, \dfrac{11}{21}, \dfrac{37}{42} 2 1 , 7 4 , 14 9 , 21 11 , 42 37
(vi) 2 7 , 5 8 , 11 14 , 9 16 , 3 4 \dfrac{2}{7}, \dfrac{5}{8}, \dfrac{11}{14}, \dfrac{9}{16}, \dfrac{3}{4} 7 2 , 8 5 , 14 11 , 16 9 , 4 3
Answer
(i) 4 5 , 7 10 , 11 15 , 13 20 \dfrac{4}{5}, \dfrac{7}{10}, \dfrac{11}{15}, \dfrac{13}{20} 5 4 , 10 7 , 15 11 , 20 13
Denominators: 5, 10, 15, 20
LCM = 60.
Equivalent fractions:
⇒ 4 × 12 5 × 12 , 7 × 6 10 × 6 , 11 × 4 15 × 4 , 13 × 3 20 × 3 ⇒ 48 60 , 42 60 , 44 60 , 39 60 \Rightarrow \dfrac{4 \times 12}{5 \times 12}, \dfrac{7 \times 6}{10 \times 6}, \dfrac{11 \times 4}{15 \times 4}, \dfrac{13 \times 3}{20 \times 3}\\[1em] \Rightarrow \dfrac{48}{60}, \dfrac{42}{60}, \dfrac{44}{60}, \dfrac{39}{60} ⇒ 5 × 12 4 × 12 , 10 × 6 7 × 6 , 15 × 4 11 × 4 , 20 × 3 13 × 3 ⇒ 60 48 , 60 42 , 60 44 , 60 39
Hence, the like fractions are 48 60 , 42 60 , 44 60 , 39 60 \dfrac{48}{60}, \dfrac{42}{60}, \dfrac{44}{60}, \dfrac{39}{60} 60 48 , 60 42 , 60 44 , 60 39 .
(ii) 2 3 , 1 4 , 5 6 , 7 8 , 11 12 \dfrac{2}{3}, \dfrac{1}{4}, \dfrac{5}{6}, \dfrac{7}{8}, \dfrac{11}{12} 3 2 , 4 1 , 6 5 , 8 7 , 12 11
Denominators: 3, 4, 6, 8 and 12
LCM = 24.
Equivalent fractions:
⇒ 2 × 8 3 × 8 , 1 × 6 4 × 6 , 5 × 4 6 × 4 , 7 × 3 8 × 3 , 11 × 2 12 × 2 ⇒ 16 24 , 6 24 , 20 24 , 21 24 , 22 24 \Rightarrow \dfrac{2 \times 8}{3 \times 8}, \dfrac{1 \times 6}{4 \times 6}, \dfrac{5 \times 4}{6 \times 4}, \dfrac{7 \times 3}{8 \times 3}, \dfrac{11 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{16}{24}, \dfrac{6}{24}, \dfrac{20}{24}, \dfrac{21}{24}, \dfrac{22}{24} ⇒ 3 × 8 2 × 8 , 4 × 6 1 × 6 , 6 × 4 5 × 4 , 8 × 3 7 × 3 , 12 × 2 11 × 2 ⇒ 24 16 , 24 6 , 24 20 , 24 21 , 24 22
Hence, the like fractions are 16 24 , 6 24 , 20 24 , 21 24 , 22 24 \dfrac{16}{24}, \dfrac{6}{24}, \dfrac{20}{24}, \dfrac{21}{24}, \dfrac{22}{24} 24 16 , 24 6 , 24 20 , 24 21 , 24 22 .
(iii) 1 3 , 3 4 , 5 12 , 9 16 , 17 24 \dfrac{1}{3}, \dfrac{3}{4}, \dfrac{5}{12}, \dfrac{9}{16}, \dfrac{17}{24} 3 1 , 4 3 , 12 5 , 16 9 , 24 17
Denominators: 3, 4, 12, 16, 24
LCM = 48.
Equivalent fractions:
⇒ 1 × 16 3 × 16 , 3 × 12 4 × 12 , 5 × 4 12 × 4 , 9 × 3 16 × 3 , 17 × 2 24 × 2 ⇒ 16 48 , 36 48 , 20 48 , 27 48 , 34 48 \Rightarrow \dfrac{1 \times 16}{3 \times 16}, \dfrac{3 \times 12}{4 \times 12}, \dfrac{5 \times 4}{12 \times 4}, \dfrac{9 \times 3}{16 \times 3}, \dfrac{17 \times 2}{24 \times 2}\\[1em] \Rightarrow \dfrac{16}{48}, \dfrac{36}{48}, \dfrac{20}{48}, \dfrac{27}{48}, \dfrac{34}{48} ⇒ 3 × 16 1 × 16 , 4 × 12 3 × 12 , 12 × 4 5 × 4 , 16 × 3 9 × 3 , 24 × 2 17 × 2 ⇒ 48 16 , 48 36 , 48 20 , 48 27 , 48 34
Hence, the like fractions are 16 48 , 36 48 , 20 48 , 27 48 , 34 48 \dfrac{16}{48}, \dfrac{36}{48}, \dfrac{20}{48}, \dfrac{27}{48}, \dfrac{34}{48} 48 16 , 48 36 , 48 20 , 48 27 , 48 34 .
(iv) 2 3 , 1 6 , 5 9 , 7 12 , 13 18 \dfrac{2}{3}, \dfrac{1}{6}, \dfrac{5}{9}, \dfrac{7}{12}, \dfrac{13}{18} 3 2 , 6 1 , 9 5 , 12 7 , 18 13
Denominators: 3, 6, 9, 12, 18
LCM = 36.
Equivalent fractions:
⇒ 2 × 12 3 × 12 , 1 × 6 6 × 6 , 5 × 4 9 × 4 , 7 × 3 12 × 3 , 13 × 2 18 × 2 ⇒ 24 36 , 6 36 , 20 36 , 21 36 , 26 36 \Rightarrow \dfrac{2 \times 12}{3 \times 12}, \dfrac{1 \times 6}{6 \times 6}, \dfrac{5 \times 4}{9 \times 4}, \dfrac{7 \times 3}{12 \times 3}, \dfrac{13 \times 2}{18 \times 2}\\[1em] \Rightarrow \dfrac{24}{36}, \dfrac{6}{36}, \dfrac{20}{36}, \dfrac{21}{36}, \dfrac{26}{36} ⇒ 3 × 12 2 × 12 , 6 × 6 1 × 6 , 9 × 4 5 × 4 , 12 × 3 7 × 3 , 18 × 2 13 × 2 ⇒ 36 24 , 36 6 , 36 20 , 36 21 , 36 26
Hence, the like fractions are 24 36 , 6 36 , 20 36 , 21 36 , 26 36 \dfrac{24}{36}, \dfrac{6}{36}, \dfrac{20}{36}, \dfrac{21}{36}, \dfrac{26}{36} 36 24 , 36 6 , 36 20 , 36 21 , 36 26 .
(v) 1 2 , 4 7 , 9 14 , 11 21 , 37 42 \dfrac{1}{2}, \dfrac{4}{7}, \dfrac{9}{14}, \dfrac{11}{21}, \dfrac{37}{42} 2 1 , 7 4 , 14 9 , 21 11 , 42 37
Denominators: 2, 7, 14, 21, 42
LCM = 42.
Equivalent fractions:
⇒ 1 × 21 2 × 21 , 4 × 6 7 × 6 , 9 × 3 14 × 3 , 11 × 2 21 × 2 , 37 × 1 42 × 1 ⇒ 21 42 , 24 42 , 27 42 , 22 42 , 37 42 \Rightarrow \dfrac{1 \times 21}{2 \times 21}, \dfrac{4 \times 6}{7 \times 6}, \dfrac{9 \times 3}{14 \times 3}, \dfrac{11 \times 2}{21 \times 2}, \dfrac{37 \times 1}{42 \times 1}\\[1em] \Rightarrow \dfrac{21}{42}, \dfrac{24}{42}, \dfrac{27}{42}, \dfrac{22}{42}, \dfrac{37}{42} ⇒ 2 × 21 1 × 21 , 7 × 6 4 × 6 , 14 × 3 9 × 3 , 21 × 2 11 × 2 , 42 × 1 37 × 1 ⇒ 42 21 , 42 24 , 42 27 , 42 22 , 42 37
Hence, the like fractions are 21 42 , 24 42 , 27 42 , 22 42 , 37 42 \dfrac{21}{42}, \dfrac{24}{42}, \dfrac{27}{42}, \dfrac{22}{42}, \dfrac{37}{42} 42 21 , 42 24 , 42 27 , 42 22 , 42 37 .
(vi) 2 7 , 5 8 , 11 14 , 9 16 , 3 4 \dfrac{2}{7}, \dfrac{5}{8}, \dfrac{11}{14}, \dfrac{9}{16}, \dfrac{3}{4} 7 2 , 8 5 , 14 11 , 16 9 , 4 3
Denominators: 7, 8, 14, 16, 4
LCM = 112.
Equivalent fractions:
⇒ 2 × 16 7 × 16 , 5 × 14 8 × 14 , 11 × 8 14 × 8 , 9 × 7 16 × 7 , 3 × 28 4 × 28 ⇒ 32 112 , 70 112 , 88 112 , 63 112 , 84 112 \Rightarrow \dfrac{2 \times 16}{7 \times 16}, \dfrac{5 \times 14}{8 \times 14}, \dfrac{11 \times 8}{14 \times 8}, \dfrac{9 \times 7}{16 \times 7}, \dfrac{3 \times 28}{4 \times 28}\\[1em] \Rightarrow \dfrac{32}{112}, \dfrac{70}{112}, \dfrac{88}{112}, \dfrac{63}{112}, \dfrac{84}{112} ⇒ 7 × 16 2 × 16 , 8 × 14 5 × 14 , 14 × 8 11 × 8 , 16 × 7 9 × 7 , 4 × 28 3 × 28 ⇒ 112 32 , 112 70 , 112 88 , 112 63 , 112 84
Hence, the like fractions are 32 112 , 70 112 , 88 112 , 63 112 , 84 112 \dfrac{32}{112}, \dfrac{70}{112}, \dfrac{88}{112}, \dfrac{63}{112}, \dfrac{84}{112} 112 32 , 112 70 , 112 88 , 112 63 , 112 84 .
Fill in the placeholders with > or < :
(i) 7 9 63 5 9 \dfrac{7}{9} {\boxed{\phantom{63}}} \dfrac{5}{9} 9 7 63 9 5
(ii) 9 13 63 11 13 \dfrac{9}{13} {\boxed{\phantom{63}}} \dfrac{11}{13} 13 9 63 13 11
(iii) 3 5 63 3 4 \dfrac{3}{5} {\boxed{\phantom{63}}} \dfrac{3}{4} 5 3 63 4 3
(iv) 7 9 63 7 11 \dfrac{7}{9} {\boxed{\phantom{63}}} \dfrac{7}{11} 9 7 63 11 7
(v) 5 8 63 5 6 \dfrac{5}{8} {\boxed{\phantom{63}}} \dfrac{5}{6} 8 5 63 6 5
(vi) 7 9 63 6 11 \dfrac{7}{9} {\boxed{\phantom{63}}} \dfrac{6}{11} 9 7 63 11 6
(vii) 6 5 63 5 4 \dfrac{6}{5} {\boxed{\phantom{63}}} \dfrac{5}{4} 5 6 63 4 5
(viii) 7 11 63 8 13 \dfrac{7}{11} {\boxed{\phantom{63}}} \dfrac{8}{13} 11 7 63 13 8
(ix) 10 13 63 13 16 \dfrac{10}{13} {\boxed{\phantom{63}}} \dfrac{13}{16} 13 10 63 16 13
(x) 2 9 63 3 14 \dfrac{2}{9} {\boxed{\phantom{63}}} \dfrac{3}{14} 9 2 63 14 3
(xi) 7 12 63 5 9 \dfrac{7}{12} {\boxed{\phantom{63}}} \dfrac{5}{9} 12 7 63 9 5
(xii) 15 19 63 3 4 \dfrac{15}{19} {\boxed{\phantom{63}}} \dfrac{3}{4} 19 15 63 4 3
Answer
(i) 7 9 63 5 9 \dfrac{7}{9} {\boxed{\phantom{63}}} \dfrac{5}{9} 9 7 63 9 5
Among two fractions with same denominator, the one with greater numerator is greater of the two.
Hence, 7 9 > 5 9 \dfrac{7}{9} {\boxed{\gt}} \dfrac{5}{9} 9 7 > 9 5 .
(ii) 9 13 63 11 13 \dfrac{9}{13} {\boxed{\phantom{63}}} \dfrac{11}{13} 13 9 63 13 11
Among two fractions with same denominator, the one with greater numerator is greater of the two.
Hence, 9 13 < 11 13 \dfrac{9}{13} {\boxed \lt} \dfrac{11}{13} 13 9 < 13 11 .
(iii) 3 5 63 3 4 \dfrac{3}{5} {\boxed{\phantom{63}}} \dfrac{3}{4} 5 3 63 4 3
Among two fractions with same numerator, the one with smaller denominator is greater of the two.
Hence, 3 5 < 3 4 \dfrac{3}{5} {\boxed{\lt}} \dfrac{3}{4} 5 3 < 4 3 .
(iv) 7 9 \dfrac{7}{9} 9 7 63 {\boxed{\phantom{63}}} 63 7 11 \dfrac{7}{11} 11 7
Among two fractions with same numerator, the one with smaller denominator is greater of the two.
Hence, 7 9 \dfrac{7}{9} 9 7 > {\boxed{\gt}} > 7 11 \dfrac{7}{11} 11 7
(v) 5 8 63 5 6 \dfrac{5}{8} {\boxed{\phantom{63}}} \dfrac{5}{6} 8 5 63 6 5
Among two fractions with same numerator, the one with smaller denominator is greater of the two.
Hence, 5 8 < 5 6 \dfrac{5}{8} {\boxed{\lt}} \dfrac{5}{6} 8 5 < 6 5 .
(vi) 7 9 63 6 11 \dfrac{7}{9} {\boxed{\phantom{63}}} \dfrac{6}{11} 9 7 63 11 6
Cross multiply; 7 x 11 and 6 x 9
⇒ 77 and 54
Now, comparing both numbers;
⇒ 77 > 54
Hence, 7 9 > 6 11 \dfrac{7}{9} {\boxed{\gt}} \dfrac{6}{11} 9 7 > 11 6 .
(vii) 6 5 63 5 4 \dfrac{6}{5} {\boxed{\phantom{63}}} \dfrac{5}{4} 5 6 63 4 5
Cross multiply; 6 x 4 and 5 x 5
⇒ 24 and 25
Now, comparing both numbers;
⇒ 24 < 25
Hence, 6 5 < 5 4 \dfrac{6}{5} {\boxed{\lt}} \dfrac{5}{4} 5 6 < 4 5 .
(viii) 7 11 63 8 13 \dfrac{7}{11} {\boxed{\phantom{63}}} \dfrac{8}{13} 11 7 63 13 8
Cross multiply; 7 x 13 and 8 x 11
⇒ 91 and 88
Now, comparing both numbers;
⇒ 91 > 88
Hence, 7 11 > 8 13 \dfrac{7}{11} {\boxed{\gt}} \dfrac{8}{13} 11 7 > 13 8 .
(ix) 10 13 63 13 16 \dfrac{10}{13} {\boxed{\phantom{63}}} \dfrac{13}{16} 13 10 63 16 13
Cross multiply; 10 x 16 and 13 x 13
⇒ 160 and 169
Now, comparing both numbers;
⇒ 160 < 169
Hence, 10 13 < 13 16 \dfrac{10}{13} {\boxed{\lt}} \dfrac{13}{16} 13 10 < 16 13 .
(x) 2 9 63 3 14 \dfrac{2}{9} {\boxed{\phantom{63}}} \dfrac{3}{14} 9 2 63 14 3
Cross multiply; 2 x 14 and 3 x 9
⇒ 28 and 27
Now, comparing both numbers;
⇒ 28 > 27
Hence, 2 9 > 3 14 \dfrac{2}{9} {\boxed{\gt}} \dfrac{3}{14} 9 2 > 14 3 .
(xi) 7 12 63 5 9 \dfrac{7}{12} {\boxed{\phantom{63}}} \dfrac{5}{9} 12 7 63 9 5
Cross multiply; 7 x 9 and 12 x 5
⇒ 63 and 60
Now, comparing both numbers;
⇒ 63 > 60
Hence, 7 12 > 5 9 \dfrac{7}{12} {\boxed{\gt}} \dfrac{5}{9} 12 7 > 9 5 .
(xii) 15 19 63 3 4 \dfrac{15}{19} {\boxed{\phantom{63}}} \dfrac{3}{4} 19 15 63 4 3
Cross multiply; 15 x 4 and 3 x 19
⇒ 60 and 57
Now, comparing both numbers;
⇒ 60 > 57
Hence, 15 19 > 3 4 \dfrac{15}{19} {\boxed{\gt}} \dfrac{3}{4} 19 15 > 4 3 .
Arrange the following fractions in ascending order :
(i) 3 11 , 9 11 , 4 11 , 5 11 , 1 11 \dfrac{3}{11}, \dfrac{9}{11}, \dfrac{4}{11}, \dfrac{5}{11}, \dfrac{1}{11} 11 3 , 11 9 , 11 4 , 11 5 , 11 1
(ii) 2 13 , 2 9 , 2 15 , 2 7 , 2 5 \dfrac{2}{13}, \dfrac{2}{9}, \dfrac{2}{15}, \dfrac{2}{7}, \dfrac{2}{5} 13 2 , 9 2 , 15 2 , 7 2 , 5 2
(iii) 2 3 , 5 6 , 7 9 , 11 12 , 13 18 \dfrac{2}{3}, \dfrac{5}{6}, \dfrac{7}{9}, \dfrac{11}{12}, \dfrac{13}{18} 3 2 , 6 5 , 9 7 , 12 11 , 18 13
(iv) 2 3 , 1 4 , 5 6 , 3 8 , 7 12 \dfrac{2}{3}, \dfrac{1}{4}, \dfrac{5}{6}, \dfrac{3}{8}, \dfrac{7}{12} 3 2 , 4 1 , 6 5 , 8 3 , 12 7
Answer
(i) 3 11 , 9 11 , 4 11 , 5 11 , 1 11 \dfrac{3}{11}, \dfrac{9}{11}, \dfrac{4}{11}, \dfrac{5}{11}, \dfrac{1}{11} 11 3 , 11 9 , 11 4 , 11 5 , 11 1
Among two fractions with same denominator, the one with greater numerator is greater of the two.
Hence, 1 11 < 3 11 < 4 11 < 5 11 < 9 11 \dfrac{1}{11} \lt \dfrac{3}{11} \lt \dfrac{4}{11} \lt \dfrac{5}{11} \lt \dfrac{9}{11} 11 1 < 11 3 < 11 4 < 11 5 < 11 9
(ii) 2 13 , 2 9 , 2 15 , 2 7 , 2 5 \dfrac{2}{13}, \dfrac{2}{9}, \dfrac{2}{15}, \dfrac{2}{7}, \dfrac{2}{5} 13 2 , 9 2 , 15 2 , 7 2 , 5 2
Among two fractions with same numerator, the one with smaller denominator is greater of the two.
Hence, 2 15 < 2 13 < 2 9 < 2 7 < 2 5 \dfrac{2}{15} \lt \dfrac{2}{13} \lt \dfrac{2}{9} \lt \dfrac{2}{7} \lt \dfrac{2}{5} 15 2 < 13 2 < 9 2 < 7 2 < 5 2
(iii) 2 3 , 5 6 , 7 9 , 11 12 , 13 18 \dfrac{2}{3}, \dfrac{5}{6}, \dfrac{7}{9}, \dfrac{11}{12}, \dfrac{13}{18} 3 2 , 6 5 , 9 7 , 12 11 , 18 13
LCM of the denominators (3, 6, 9, 12, 18) = 36
⇒ 2 × 12 3 × 12 , 5 × 6 6 × 6 , 7 × 4 9 × 4 , 11 × 3 12 × 3 , 13 × 2 18 × 2 ⇒ 24 36 , 30 36 , 28 36 , 33 36 , 26 36 \Rightarrow \dfrac{2 \times 12}{3 \times 12}, \dfrac{5 \times 6}{6 \times 6}, \dfrac{7 \times 4}{9 \times 4}, \dfrac{11 \times 3}{12 \times 3}, \dfrac{13 \times 2}{18 \times 2}\\[1em] \Rightarrow \dfrac{24}{36}, \dfrac{30}{36}, \dfrac{28}{36}, \dfrac{33}{36}, \dfrac{26}{36} ⇒ 3 × 12 2 × 12 , 6 × 6 5 × 6 , 9 × 4 7 × 4 , 12 × 3 11 × 3 , 18 × 2 13 × 2 ⇒ 36 24 , 36 30 , 36 28 , 36 33 , 36 26
Among two fractions with same denominator, the one with greater numerator is greater of the two.
24 36 < 26 36 < 28 36 < 30 36 < 33 36 \dfrac{24}{36} \lt \dfrac{26}{36} \lt \dfrac{28}{36} \lt \dfrac{30}{36} \lt \dfrac{33}{36} 36 24 < 36 26 < 36 28 < 36 30 < 36 33
Hence, 2 3 < 13 18 < 7 9 < 5 6 < 11 12 \dfrac{2}{3} \lt \dfrac{13}{18} \lt \dfrac{7}{9} \lt \dfrac{5}{6} \lt \dfrac{11}{12} 3 2 < 18 13 < 9 7 < 6 5 < 12 11
(iv) 2 3 , 1 4 , 5 6 , 3 8 , 7 12 \dfrac{2}{3}, \dfrac{1}{4}, \dfrac{5}{6}, \dfrac{3}{8}, \dfrac{7}{12} 3 2 , 4 1 , 6 5 , 8 3 , 12 7
LCM of the denominators (3, 4, 6, 8, 12) = 24
⇒ 2 × 8 3 × 8 , 1 × 6 4 × 6 , 5 × 4 6 × 4 , 3 × 3 8 × 3 , 7 × 2 12 × 2 ⇒ 16 24 , 6 24 , 20 24 , 9 24 , 14 24 \Rightarrow \dfrac{2 \times 8}{3 \times 8}, \dfrac{1 \times 6}{4 \times 6}, \dfrac{5 \times 4}{6 \times 4}, \dfrac{3 \times 3}{8 \times 3}, \dfrac{7 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{16}{24}, \dfrac{6}{24}, \dfrac{20}{24}, \dfrac{9}{24}, \dfrac{14}{24} ⇒ 3 × 8 2 × 8 , 4 × 6 1 × 6 , 6 × 4 5 × 4 , 8 × 3 3 × 3 , 12 × 2 7 × 2 ⇒ 24 16 , 24 6 , 24 20 , 24 9 , 24 14
Among two fractions with same denominator, the one with greater numerator is greater of the two.
6 24 < 9 24 < 14 24 < 16 24 < 20 24 \dfrac{6}{24} \lt \dfrac{9}{24} \lt \dfrac{14}{24} \lt \dfrac{16}{24} \lt \dfrac{20}{24} 24 6 < 24 9 < 24 14 < 24 16 < 24 20
Hence, 1 4 < 3 8 < 7 12 < 2 3 < 5 6 \dfrac{1}{4} \lt \dfrac{3}{8} \lt \dfrac{7}{12} \lt \dfrac{2}{3} \lt \dfrac{5}{6} 4 1 < 8 3 < 12 7 < 3 2 < 6 5
Arrange the following fractions in descending order :
(i) 5 12 , 1 12 , 7 12 , 11 12 , 9 12 \dfrac{5}{12}, \dfrac{1}{12}, \dfrac{7}{12}, \dfrac{11}{12}, \dfrac{9}{12} 12 5 , 12 1 , 12 7 , 12 11 , 12 9
(ii) 4 7 , 4 3 , 4 9 , 4 5 , 4 11 \dfrac{4}{7}, \dfrac{4}{3}, \dfrac{4}{9}, \dfrac{4}{5}, \dfrac{4}{11} 7 4 , 3 4 , 9 4 , 5 4 , 11 4
(iii) 2 3 , 5 6 , 7 9 , 3 4 , 1 2 \dfrac{2}{3}, \dfrac{5}{6}, \dfrac{7}{9}, \dfrac{3}{4}, \dfrac{1}{2} 3 2 , 6 5 , 9 7 , 4 3 , 2 1
(iv) 2 3 , 3 5 , 7 10 , 8 15 , 11 20 \dfrac{2}{3}, \dfrac{3}{5}, \dfrac{7}{10}, \dfrac{8}{15}, \dfrac{11}{20} 3 2 , 5 3 , 10 7 , 15 8 , 20 11
(v) 17 32 , 7 12 , 19 48 , 13 24 , 9 16 \dfrac{17}{32}, \dfrac{7}{12}, \dfrac{19}{48}, \dfrac{13}{24}, \dfrac{9}{16} 32 17 , 12 7 , 48 19 , 24 13 , 16 9
(vi) 5 6 , 7 9 , 17 24 , 3 4 , 23 36 \dfrac{5}{6}, \dfrac{7}{9}, \dfrac{17}{24}, \dfrac{3}{4}, \dfrac{23}{36} 6 5 , 9 7 , 24 17 , 4 3 , 36 23
Answer
(i) 5 12 , 1 12 , 7 12 , 11 12 , 9 12 \dfrac{5}{12}, \dfrac{1}{12}, \dfrac{7}{12}, \dfrac{11}{12}, \dfrac{9}{12} 12 5 , 12 1 , 12 7 , 12 11 , 12 9
Among two fractions with same denominator, the one with greater numerator is greater of the two.
11 12 > 9 12 > 7 12 > 5 12 > 1 12 \dfrac{11}{12} \gt \dfrac{9}{12} \gt \dfrac{7}{12} \gt \dfrac{5}{12} \gt \dfrac{1}{12} 12 11 > 12 9 > 12 7 > 12 5 > 12 1
Hence, 11 12 > 9 12 > 7 12 > 5 12 > 1 12 \dfrac{11}{12} \gt \dfrac{9}{12} \gt \dfrac{7}{12} \gt \dfrac{5}{12} \gt \dfrac{1}{12} 12 11 > 12 9 > 12 7 > 12 5 > 12 1 .
(ii) 4 7 , 4 3 , 4 9 , 4 5 , 4 11 \dfrac{4}{7}, \dfrac{4}{3}, \dfrac{4}{9}, \dfrac{4}{5}, \dfrac{4}{11} 7 4 , 3 4 , 9 4 , 5 4 , 11 4
Among two fractions with same numerator, the one with smaller denominator is greater of the two.
4 3 > 4 5 > 4 7 > 4 9 > 4 11 \dfrac{4}{3} \gt \dfrac{4}{5} \gt \dfrac{4}{7} \gt \dfrac{4}{9} \gt \dfrac{4}{11} 3 4 > 5 4 > 7 4 > 9 4 > 11 4
Hence, 4 3 > 4 5 > 4 7 > 4 9 > 4 11 \dfrac{4}{3} \gt \dfrac{4}{5} \gt \dfrac{4}{7} \gt \dfrac{4}{9} \gt \dfrac{4}{11} 3 4 > 5 4 > 7 4 > 9 4 > 11 4 .
(iii) 2 3 , 5 6 , 7 9 , 3 4 , 1 2 \dfrac{2}{3}, \dfrac{5}{6}, \dfrac{7}{9}, \dfrac{3}{4}, \dfrac{1}{2} 3 2 , 6 5 , 9 7 , 4 3 , 2 1
LCM of the denominators (3, 6, 9, 4, 2) = 36
⇒ 2 × 12 3 × 12 , 5 × 6 6 × 6 , 7 × 4 9 × 4 , 3 × 9 4 × 9 , 1 × 18 2 × 18 ⇒ 24 36 , 30 36 , 28 36 , 27 36 , 18 36 \Rightarrow \dfrac{2 \times 12}{3 \times 12}, \dfrac{5 \times 6}{6 \times 6}, \dfrac{7 \times 4}{9 \times 4}, \dfrac{3 \times 9}{4 \times 9}, \dfrac{1 \times 18}{2 \times 18}\\[1em] \Rightarrow \dfrac{24}{36}, \dfrac{30}{36}, \dfrac{28}{36}, \dfrac{27}{36}, \dfrac{18}{36} ⇒ 3 × 12 2 × 12 , 6 × 6 5 × 6 , 9 × 4 7 × 4 , 4 × 9 3 × 9 , 2 × 18 1 × 18 ⇒ 36 24 , 36 30 , 36 28 , 36 27 , 36 18
Among two fractions with same denominator, the one with greater numerator is greater of the two.
30 36 > 28 36 > 27 36 > 24 36 > 18 36 \dfrac{30}{36} \gt \dfrac{28}{36} \gt \dfrac{27}{36} \gt \dfrac{24}{36} \gt \dfrac{18}{36} 36 30 > 36 28 > 36 27 > 36 24 > 36 18
Hence, 5 6 > 7 9 > 3 4 > 2 3 > 1 2 \dfrac{5}{6} \gt \dfrac{7}{9} \gt \dfrac{3}{4} \gt \dfrac{2}{3} \gt \dfrac{1}{2} 6 5 > 9 7 > 4 3 > 3 2 > 2 1
(iv) 2 3 , 3 5 , 7 10 , 8 15 , 11 20 \dfrac{2}{3}, \dfrac{3}{5}, \dfrac{7}{10}, \dfrac{8}{15}, \dfrac{11}{20} 3 2 , 5 3 , 10 7 , 15 8 , 20 11
LCM of the denominators (3, 5, 10, 15, 20) = 60
⇒ 2 × 20 3 × 20 , 3 × 12 5 × 12 , 7 × 6 10 × 6 , 8 × 4 15 × 4 , 11 × 3 20 × 3 ⇒ 40 60 , 36 60 , 42 60 , 32 60 , 33 60 \Rightarrow \dfrac{2 \times 20}{3 \times 20}, \dfrac{3 \times 12}{5 \times 12}, \dfrac{7 \times 6}{10 \times 6}, \dfrac{8 \times 4}{15 \times 4}, \dfrac{11 \times 3}{20 \times 3}\\[1em] \Rightarrow \dfrac{40}{60}, \dfrac{36}{60}, \dfrac{42}{60}, \dfrac{32}{60}, \dfrac{33}{60} ⇒ 3 × 20 2 × 20 , 5 × 12 3 × 12 , 10 × 6 7 × 6 , 15 × 4 8 × 4 , 20 × 3 11 × 3 ⇒ 60 40 , 60 36 , 60 42 , 60 32 , 60 33
Among two fractions with same denominator, the one with greater numerator is greater of the two.
42 60 > 40 60 > 36 60 > 33 60 > 32 60 \dfrac{42}{60} \gt \dfrac{40}{60} \gt \dfrac{36}{60} \gt \dfrac{33}{60} \gt \dfrac{32}{60} 60 42 > 60 40 > 60 36 > 60 33 > 60 32
Hence, 7 10 > 2 3 > 3 5 > 11 20 > 8 15 \dfrac{7}{10} \gt \dfrac{2}{3} \gt \dfrac{3}{5} \gt \dfrac{11}{20} \gt \dfrac{8}{15} 10 7 > 3 2 > 5 3 > 20 11 > 15 8
(v) 17 32 , 7 12 , 19 48 , 13 24 , 9 16 \dfrac{17}{32}, \dfrac{7}{12}, \dfrac{19}{48}, \dfrac{13}{24}, \dfrac{9}{16} 32 17 , 12 7 , 48 19 , 24 13 , 16 9
LCM of the denominators (32, 12, 48, 24, 16) = 96
⇒ 17 × 3 32 × 3 , 7 × 8 12 × 8 , 19 × 2 48 × 2 , 13 × 4 24 × 4 , 9 × 6 16 × 6 ⇒ 51 96 , 56 96 , 38 96 , 52 96 , 54 96 \Rightarrow \dfrac{17 \times 3}{32 \times 3}, \dfrac{7 \times 8}{12 \times 8}, \dfrac{19 \times 2}{48 \times 2}, \dfrac{13 \times 4}{24 \times 4}, \dfrac{9 \times 6}{16 \times 6}\\[1em] \Rightarrow \dfrac{51}{96}, \dfrac{56}{96}, \dfrac{38}{96}, \dfrac{52}{96}, \dfrac{54}{96} ⇒ 32 × 3 17 × 3 , 12 × 8 7 × 8 , 48 × 2 19 × 2 , 24 × 4 13 × 4 , 16 × 6 9 × 6 ⇒ 96 51 , 96 56 , 96 38 , 96 52 , 96 54
Among two fractions with same denominator, the one with greater numerator is greater of the two.
56 96 > 54 96 > 52 96 > 51 96 > 38 96 \dfrac{56}{96} \gt \dfrac{54}{96} \gt \dfrac{52}{96} \gt \dfrac{51}{96} \gt \dfrac{38}{96} 96 56 > 96 54 > 96 52 > 96 51 > 96 38
Hence, 7 12 > 9 16 > 13 24 > 17 32 > 19 48 \dfrac{7}{12} \gt \dfrac{9}{16} \gt \dfrac{13}{24} \gt \dfrac{17}{32} \gt \dfrac{19}{48} 12 7 > 16 9 > 24 13 > 32 17 > 48 19
(vi) 5 6 , 7 9 , 17 24 , 3 4 , 23 36 \dfrac{5}{6}, \dfrac{7}{9}, \dfrac{17}{24}, \dfrac{3}{4}, \dfrac{23}{36} 6 5 , 9 7 , 24 17 , 4 3 , 36 23
LCM of the denominators (6, 9, 24, 4, 36) = 72
⇒ 5 × 12 6 × 12 , 7 × 8 9 × 8 , 17 × 3 24 × 3 , 3 × 18 4 × 18 , 23 × 2 36 × 2 ⇒ 60 72 , 56 72 , 51 72 , 54 72 , 46 72 \Rightarrow \dfrac{5 \times 12}{6 \times 12}, \dfrac{7 \times 8}{9 \times 8}, \dfrac{17 \times 3}{24 \times 3}, \dfrac{3 \times 18}{4 \times 18}, \dfrac{23 \times 2}{36 \times 2}\\[1em] \Rightarrow \dfrac{60}{72}, \dfrac{56}{72}, \dfrac{51}{72}, \dfrac{54}{72}, \dfrac{46}{72} ⇒ 6 × 12 5 × 12 , 9 × 8 7 × 8 , 24 × 3 17 × 3 , 4 × 18 3 × 18 , 36 × 2 23 × 2 ⇒ 72 60 , 72 56 , 72 51 , 72 54 , 72 46
Among two fractions with same denominator, the one with greater numerator is greater of the two.
60 72 > 56 72 > 54 72 > 51 72 > 46 72 \dfrac{60}{72} \gt \dfrac{56}{72} \gt \dfrac{54}{72} \gt \dfrac{51}{72} \gt \dfrac{46}{72} 72 60 > 72 56 > 72 54 > 72 51 > 72 46
Hence, 5 6 > 7 9 > 3 4 > 17 24 > 23 36 \dfrac{5}{6} \gt \dfrac{7}{9} \gt \dfrac{3}{4} \gt \dfrac{17}{24} \gt \dfrac{23}{36} 6 5 > 9 7 > 4 3 > 24 17 > 36 23
Find the sum :
(i) 2 7 + 3 7 \dfrac{2}{7} + \dfrac{3}{7} 7 2 + 7 3
(ii) 5 8 + 1 8 \dfrac{5}{8} + \dfrac{1}{8} 8 5 + 8 1
(iii) 7 9 + 4 9 \dfrac{7}{9} + \dfrac{4}{9} 9 7 + 9 4
(iv) 1 5 6 + 1 6 1\dfrac{5}{6} + \dfrac{1}{6} 1 6 5 + 6 1
Answer
(i) 2 7 + 3 7 \dfrac{2}{7} + \dfrac{3}{7} 7 2 + 7 3
⇒ 2 + 3 7 ⇒ 5 7 \Rightarrow \dfrac{2 + 3}{7}\\[1em] \Rightarrow \dfrac{5}{7}\\[1em] ⇒ 7 2 + 3 ⇒ 7 5
Hence, 2 7 + 3 7 = 5 7 \dfrac{2}{7} + \dfrac{3}{7} = \dfrac{5}{7} 7 2 + 7 3 = 7 5 .
(ii) 5 8 + 1 8 \dfrac{5}{8} + \dfrac{1}{8} 8 5 + 8 1
⇒ 5 + 1 8 ⇒ 6 8 ⇒ 3 4 \Rightarrow \dfrac{5 + 1}{8}\\[1em] \Rightarrow \dfrac{6}{8}\\[1em] \Rightarrow \dfrac{3}{4}\\[1em] ⇒ 8 5 + 1 ⇒ 8 6 ⇒ 4 3
Hence, 5 8 + 1 8 = 3 4 \dfrac{5}{8} + \dfrac{1}{8} = \dfrac{3}{4} 8 5 + 8 1 = 4 3 .
(iii) 7 9 + 4 9 \dfrac{7}{9} + \dfrac{4}{9} 9 7 + 9 4
⇒ 7 + 4 9 ⇒ 11 9 ⇒ 1 2 9 \Rightarrow \dfrac{7 + 4}{9}\\[1em] \Rightarrow \dfrac{11}{9}\\[1em] \Rightarrow 1\dfrac{2}{9}\\[1em] ⇒ 9 7 + 4 ⇒ 9 11 ⇒ 1 9 2
Hence, 7 9 + 4 9 = 1 2 9 \dfrac{7}{9} + \dfrac{4}{9} = 1\dfrac{2}{9} 9 7 + 9 4 = 1 9 2 .
(iv) 1 5 6 + 1 6 1\dfrac{5}{6} + \dfrac{1}{6} 1 6 5 + 6 1
⇒ 11 6 + 1 6 ⇒ 11 + 1 6 ⇒ 12 6 ⇒ 2 \Rightarrow \dfrac{11}{6} + \dfrac{1}{6}\\[1em] \Rightarrow \dfrac{11 + 1}{6}\\[1em] \Rightarrow \dfrac{12}{6}\\[1em] \Rightarrow 2 ⇒ 6 11 + 6 1 ⇒ 6 11 + 1 ⇒ 6 12 ⇒ 2
Hence, 1 5 6 + 1 6 1\dfrac{5}{6} + \dfrac{1}{6} 1 6 5 + 6 1 = 2.
Find the sum :
(i) 5 14 + 3 14 + 1 14 \dfrac{5}{14} + \dfrac{3}{14} + \dfrac{1}{14} 14 5 + 14 3 + 14 1
(ii) 7 12 + 5 12 + 11 12 \dfrac{7}{12} + \dfrac{5}{12} + \dfrac{11}{12} 12 7 + 12 5 + 12 11
(iii) 1 7 8 + 3 8 + 1 5 8 1\dfrac{7}{8} + \dfrac{3}{8} + 1\dfrac{5}{8} 1 8 7 + 8 3 + 1 8 5
Answer
(i) 5 14 + 3 14 + 1 14 \dfrac{5}{14} + \dfrac{3}{14} + \dfrac{1}{14} 14 5 + 14 3 + 14 1
⇒ 5 + 3 + 1 14 ⇒ 9 14 \Rightarrow \dfrac{5 + 3 + 1}{14}\\[1em] \Rightarrow \dfrac{9}{14}\\[1em] ⇒ 14 5 + 3 + 1 ⇒ 14 9
Hence, 5 14 + 3 14 + 1 14 = 9 14 \dfrac{5}{14} + \dfrac{3}{14} + \dfrac{1}{14} = \dfrac{9}{14} 14 5 + 14 3 + 14 1 = 14 9 .
(ii) 7 12 + 5 12 + 11 12 \dfrac{7}{12} + \dfrac{5}{12} + \dfrac{11}{12} 12 7 + 12 5 + 12 11
⇒ 7 + 5 + 11 12 ⇒ 23 12 ⇒ 1 11 12 \Rightarrow \dfrac{7 + 5 + 11}{12}\\[1em] \Rightarrow \dfrac{23}{12}\\[1em] \Rightarrow 1\dfrac{11}{12}\\[1em] ⇒ 12 7 + 5 + 11 ⇒ 12 23 ⇒ 1 12 11
Hence, 7 12 + 5 12 + 11 12 = 1 11 12 \dfrac{7}{12} + \dfrac{5}{12} + \dfrac{11}{12} = 1\dfrac{11}{12} 12 7 + 12 5 + 12 11 = 1 12 11 .
(iii) 1 7 8 + 3 8 + 1 5 8 1\dfrac{7}{8} + \dfrac{3}{8} + 1\dfrac{5}{8} 1 8 7 + 8 3 + 1 8 5
⇒ 15 8 + 3 8 + 13 8 ⇒ 15 + 3 + 13 8 ⇒ 31 8 ⇒ 3 7 8 \Rightarrow \dfrac{15}{8} + \dfrac{3}{8} + \dfrac{13}{8}\\[1em] \Rightarrow \dfrac{15 + 3 + 13}{8}\\[1em] \Rightarrow \dfrac{31}{8}\\[1em] \Rightarrow 3\dfrac{7}{8}\\[1em] ⇒ 8 15 + 8 3 + 8 13 ⇒ 8 15 + 3 + 13 ⇒ 8 31 ⇒ 3 8 7
Hence, 1 7 8 + 3 8 + 1 5 8 = 3 7 8 1\dfrac{7}{8} + \dfrac{3}{8} + 1\dfrac{5}{8} = 3\dfrac{7}{8} 1 8 7 + 8 3 + 1 8 5 = 3 8 7 .
Find the sum :
(i) 4 9 + 5 6 \dfrac{4}{9} + \dfrac{5}{6} 9 4 + 6 5
(ii) 5 12 + 9 16 \dfrac{5}{12} + \dfrac{9}{16} 12 5 + 16 9
(iii) 7 12 + 13 18 \dfrac{7}{12} + \dfrac{13}{18} 12 7 + 18 13
Answer
(i) 4 9 + 5 6 \dfrac{4}{9} + \dfrac{5}{6} 9 4 + 6 5
LCM of 9 and 6 = 18
⇒ 4 × 2 9 × 2 + 5 × 3 6 × 3 ⇒ 8 18 + 15 18 ⇒ 8 + 15 18 ⇒ 23 18 ⇒ 1 5 18 \Rightarrow \dfrac{4 \times 2}{9 \times 2} + \dfrac{5 \times 3}{6 \times 3}\\[1em] \Rightarrow \dfrac{8}{18} + \dfrac{15}{18}\\[1em] \Rightarrow \dfrac{8 + 15}{18}\\[1em] \Rightarrow \dfrac{23}{18}\\[1em] \Rightarrow 1\dfrac{5}{18} ⇒ 9 × 2 4 × 2 + 6 × 3 5 × 3 ⇒ 18 8 + 18 15 ⇒ 18 8 + 15 ⇒ 18 23 ⇒ 1 18 5
Hence, 4 9 + 5 6 = 1 5 18 \dfrac{4}{9} + \dfrac{5}{6} = 1\dfrac{5}{18} 9 4 + 6 5 = 1 18 5
(ii) 5 12 + 9 16 \dfrac{5}{12} + \dfrac{9}{16} 12 5 + 16 9
LCM of 12 and 16 = 48
⇒ 5 × 4 12 × 4 + 9 × 3 16 × 3 ⇒ 20 48 + 27 48 ⇒ 20 + 27 48 ⇒ 47 48 \Rightarrow \dfrac{5 \times 4}{12 \times 4} + \dfrac{9 \times 3}{16 \times 3}\\[1em] \Rightarrow \dfrac{20}{48} + \dfrac{27}{48}\\[1em] \Rightarrow \dfrac{20 + 27}{48}\\[1em] \Rightarrow \dfrac{47}{48} ⇒ 12 × 4 5 × 4 + 16 × 3 9 × 3 ⇒ 48 20 + 48 27 ⇒ 48 20 + 27 ⇒ 48 47
Hence, 5 12 + 9 16 = 47 48 \dfrac{5}{12} + \dfrac{9}{16} = \dfrac{47}{48} 12 5 + 16 9 = 48 47
(iii) 7 12 + 13 18 \dfrac{7}{12} + \dfrac{13}{18} 12 7 + 18 13
LCM of 12 and 18 = 36
⇒ 7 × 3 12 × 3 + 13 × 2 18 × 2 ⇒ 21 36 + 26 36 ⇒ 21 + 26 36 ⇒ 47 36 ⇒ 1 11 36 \Rightarrow \dfrac{7 \times 3}{12 \times 3} + \dfrac{13 \times 2}{18 \times 2}\\[1em] \Rightarrow \dfrac{21}{36} + \dfrac{26}{36}\\[1em] \Rightarrow \dfrac{21 + 26}{36}\\[1em] \Rightarrow \dfrac{47}{36}\\[1em] \Rightarrow 1\dfrac{11}{36} ⇒ 12 × 3 7 × 3 + 18 × 2 13 × 2 ⇒ 36 21 + 36 26 ⇒ 36 21 + 26 ⇒ 36 47 ⇒ 1 36 11
Hence, 7 12 + 13 18 = 1 11 36 \dfrac{7}{12} + \dfrac{13}{18} = 1\dfrac{11}{36} 12 7 + 18 13 = 1 36 11
Find the sum :
(i) 3 10 + 8 15 + 7 20 \dfrac{3}{10} + \dfrac{8}{15} + \dfrac{7}{20} 10 3 + 15 8 + 20 7
(ii) 7 8 + 9 16 + 17 24 \dfrac{7}{8} + \dfrac{9}{16} + \dfrac{17}{24} 8 7 + 16 9 + 24 17
(iii) 5 6 + 8 9 + 11 18 + 13 27 \dfrac{5}{6} + \dfrac{8}{9} + \dfrac{11}{18} + \dfrac{13}{27} 6 5 + 9 8 + 18 11 + 27 13
Answer
(i) 3 10 + 8 15 + 7 20 \dfrac{3}{10} + \dfrac{8}{15} + \dfrac{7}{20} 10 3 + 15 8 + 20 7
LCM of 10, 15 and 20 = 60
⇒ 3 × 6 10 × 6 + 8 × 4 15 × 4 + 7 × 3 20 × 3 ⇒ 18 60 + 32 60 + 21 60 ⇒ 18 + 32 + 21 60 ⇒ 71 60 ⇒ 1 11 60 \Rightarrow \dfrac{3 \times 6}{10 \times 6} + \dfrac{8 \times 4}{15 \times 4} + \dfrac{7 \times 3}{20 \times 3}\\[1em] \Rightarrow \dfrac{18}{60} + \dfrac{32}{60} + \dfrac{21}{60}\\[1em] \Rightarrow \dfrac{18 + 32 + 21}{60}\\[1em] \Rightarrow \dfrac{71}{60}\\[1em] \Rightarrow 1\dfrac{11}{60} ⇒ 10 × 6 3 × 6 + 15 × 4 8 × 4 + 20 × 3 7 × 3 ⇒ 60 18 + 60 32 + 60 21 ⇒ 60 18 + 32 + 21 ⇒ 60 71 ⇒ 1 60 11
Hence, 3 10 + 8 15 + 7 20 = 1 11 60 \dfrac{3}{10} + \dfrac{8}{15} + \dfrac{7}{20} = 1\dfrac{11}{60} 10 3 + 15 8 + 20 7 = 1 60 11
(ii) 7 8 + 9 16 + 17 24 \dfrac{7}{8} + \dfrac{9}{16} + \dfrac{17}{24} 8 7 + 16 9 + 24 17
LCM of 8, 16 and 24 = 48
⇒ 7 × 6 8 × 6 + 9 × 3 16 × 3 + 17 × 2 24 × 2 ⇒ 42 48 + 27 48 + 34 48 ⇒ 42 + 27 + 34 48 ⇒ 103 48 ⇒ 2 7 48 \Rightarrow \dfrac{7 \times 6}{8 \times 6} + \dfrac{9 \times 3}{16 \times 3} + \dfrac{17 \times 2}{24 \times 2}\\[1em] \Rightarrow \dfrac{42}{48} + \dfrac{27}{48} + \dfrac{34}{48}\\[1em] \Rightarrow \dfrac{42 + 27 + 34}{48}\\[1em] \Rightarrow \dfrac{103}{48}\\[1em] \Rightarrow 2\dfrac{7}{48} ⇒ 8 × 6 7 × 6 + 16 × 3 9 × 3 + 24 × 2 17 × 2 ⇒ 48 42 + 48 27 + 48 34 ⇒ 48 42 + 27 + 34 ⇒ 48 103 ⇒ 2 48 7
Hence, 7 8 + 9 16 + 17 24 = 2 7 48 \dfrac{7}{8} + \dfrac{9}{16} + \dfrac{17}{24} = 2\dfrac{7}{48} 8 7 + 16 9 + 24 17 = 2 48 7
(iii) 5 6 + 8 9 + 11 18 + 13 27 \dfrac{5}{6} + \dfrac{8}{9} + \dfrac{11}{18} + \dfrac{13}{27} 6 5 + 9 8 + 18 11 + 27 13
LCM of 6, 9, 18 and 27 = 54
⇒ 5 × 9 6 × 9 + 8 × 6 9 × 6 + 11 × 3 18 × 3 + 13 × 2 27 × 2 ⇒ 45 54 + 48 54 + 33 54 + 26 54 ⇒ 45 + 48 + 33 + 26 54 ⇒ 152 54 ⇒ 76 27 ⇒ 2 22 27 \Rightarrow \dfrac{5 \times 9}{6 \times 9} + \dfrac{8 \times 6}{9 \times 6} + \dfrac{11 \times 3}{18 \times 3} + \dfrac{13 \times 2}{27 \times 2}\\[1em] \Rightarrow \dfrac{45}{54} + \dfrac{48}{54} + \dfrac{33}{54} + \dfrac{26}{54}\\[1em] \Rightarrow \dfrac{45 + 48 + 33 + 26}{54}\\[1em] \Rightarrow \dfrac{152}{54}\\[1em] \Rightarrow \dfrac{76}{27}\\[1em] \Rightarrow 2\dfrac{22}{27} ⇒ 6 × 9 5 × 9 + 9 × 6 8 × 6 + 18 × 3 11 × 3 + 27 × 2 13 × 2 ⇒ 54 45 + 54 48 + 54 33 + 54 26 ⇒ 54 45 + 48 + 33 + 26 ⇒ 54 152 ⇒ 27 76 ⇒ 2 27 22
Hence, 5 6 + 8 9 + 11 18 + 13 27 = 2 22 27 \dfrac{5}{6} + \dfrac{8}{9} + \dfrac{11}{18} + \dfrac{13}{27} = 2\dfrac{22}{27} 6 5 + 9 8 + 18 11 + 27 13 = 2 27 22
Find the sum :
(i) 4 1 6 + 2 5 8 + 3 7 12 4\dfrac{1}{6} + 2\dfrac{5}{8} + 3\dfrac{7}{12} 4 6 1 + 2 8 5 + 3 12 7
(ii) 1 1 2 + 2 2 3 + 3 3 4 + 4 4 5 1\dfrac{1}{2} + 2\dfrac{2}{3} + 3\dfrac{3}{4} + 4\dfrac{4}{5} 1 2 1 + 2 3 2 + 3 4 3 + 4 5 4
(iii) 3 1 3 + 2 2 9 + 4 1 2 + 1 13 18 3\dfrac{1}{3} + 2\dfrac{2}{9} + 4\dfrac{1}{2} + 1\dfrac{13}{18} 3 3 1 + 2 9 2 + 4 2 1 + 1 18 13
Answer
(i) 4 1 6 + 2 5 8 + 3 7 12 4\dfrac{1}{6} + 2\dfrac{5}{8} + 3\dfrac{7}{12} 4 6 1 + 2 8 5 + 3 12 7
LCM of 6, 8 and 12 = 24
⇒ 25 6 + 21 8 + 43 12 ⇒ 25 × 4 6 × 4 + 21 × 3 8 × 3 + 43 × 2 12 × 2 ⇒ 100 24 + 63 24 + 86 24 ⇒ 100 + 63 + 86 24 ⇒ 249 24 ⇒ 83 8 ⇒ 10 3 8 \Rightarrow \dfrac{25}{6} + \dfrac{21}{8} + \dfrac{43}{12}\\[1em] \Rightarrow \dfrac{25 \times 4}{6 \times 4} + \dfrac{21 \times 3}{8 \times 3} + \dfrac{43 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{100}{24} + \dfrac{63}{24} + \dfrac{86}{24}\\[1em] \Rightarrow \dfrac{100 + 63 + 86}{24}\\[1em] \Rightarrow \dfrac{249}{24}\\[1em] \Rightarrow \dfrac{83}{8}\\[1em] \Rightarrow 10\dfrac{3}{8} ⇒ 6 25 + 8 21 + 12 43 ⇒ 6 × 4 25 × 4 + 8 × 3 21 × 3 + 12 × 2 43 × 2 ⇒ 24 100 + 24 63 + 24 86 ⇒ 24 100 + 63 + 86 ⇒ 24 249 ⇒ 8 83 ⇒ 10 8 3
Hence, 4 1 6 + 2 5 8 + 3 7 12 = 10 3 8 4\dfrac{1}{6} + 2\dfrac{5}{8} + 3\dfrac{7}{12} = 10\dfrac{3}{8} 4 6 1 + 2 8 5 + 3 12 7 = 10 8 3
(ii) 1 1 2 + 2 2 3 + 3 3 4 + 4 4 5 1\dfrac{1}{2} + 2\dfrac{2}{3} + 3\dfrac{3}{4} + 4\dfrac{4}{5} 1 2 1 + 2 3 2 + 3 4 3 + 4 5 4
LCM of 2, 3, 4 and 5 = 60
⇒ 3 2 + 8 3 + 15 4 + 24 5 ⇒ 3 × 30 2 × 30 + 8 × 20 3 × 20 + 15 × 15 4 × 15 + 24 × 12 5 × 12 ⇒ 90 60 + 160 60 + 225 60 + 288 60 ⇒ 90 + 160 + 225 + 288 60 ⇒ 763 60 ⇒ 12 43 60 \Rightarrow \dfrac{3}{2} + \dfrac{8}{3} + \dfrac{15}{4} + \dfrac{24}{5}\\[1em] \Rightarrow \dfrac{3 \times 30}{2 \times 30} + \dfrac{8 \times 20}{3 \times 20} + \dfrac{15 \times 15}{4 \times 15} + \dfrac{24 \times 12}{5 \times 12}\\[1em] \Rightarrow \dfrac{90}{60} + \dfrac{160}{60} + \dfrac{225}{60} + \dfrac{288}{60}\\[1em] \Rightarrow \dfrac{90 + 160 + 225 + 288}{60}\\[1em] \Rightarrow \dfrac{763}{60}\\[1em] \Rightarrow 12\dfrac{43}{60} ⇒ 2 3 + 3 8 + 4 15 + 5 24 ⇒ 2 × 30 3 × 30 + 3 × 20 8 × 20 + 4 × 15 15 × 15 + 5 × 12 24 × 12 ⇒ 60 90 + 60 160 + 60 225 + 60 288 ⇒ 60 90 + 160 + 225 + 288 ⇒ 60 763 ⇒ 12 60 43
Hence, 1 1 2 + 2 2 3 + 3 3 4 + 4 4 5 = 12 43 60 1\dfrac{1}{2} + 2\dfrac{2}{3} + 3\dfrac{3}{4} + 4\dfrac{4}{5} = 12\dfrac{43}{60} 1 2 1 + 2 3 2 + 3 4 3 + 4 5 4 = 12 60 43
(iii) 3 1 3 + 2 2 9 + 4 1 2 + 1 13 18 3\dfrac{1}{3} + 2\dfrac{2}{9} + 4\dfrac{1}{2} + 1\dfrac{13}{18} 3 3 1 + 2 9 2 + 4 2 1 + 1 18 13
LCM of 3, 9, 2 and 18 = 18
⇒ 10 3 + 20 9 + 9 2 + 31 18 ⇒ 10 × 6 3 × 6 + 20 × 2 9 × 2 + 9 × 9 2 × 9 + 31 × 1 18 × 1 ⇒ 60 18 + 40 18 + 81 18 + 31 18 ⇒ 60 + 40 + 81 + 31 18 ⇒ 212 18 ⇒ 106 9 ⇒ 11 7 9 \Rightarrow \dfrac{10}{3} + \dfrac{20}{9} + \dfrac{9}{2} + \dfrac{31}{18}\\[1em] \Rightarrow \dfrac{10 \times 6}{3 \times 6} + \dfrac{20 \times 2}{9 \times 2} + \dfrac{9 \times 9}{2 \times 9} + \dfrac{31 \times 1}{18 \times 1}\\[1em] \Rightarrow \dfrac{60}{18} + \dfrac{40}{18} + \dfrac{81}{18} + \dfrac{31}{18}\\[1em] \Rightarrow \dfrac{60 + 40 + 81 + 31}{18}\\[1em] \Rightarrow \dfrac{212}{18}\\[1em] \Rightarrow \dfrac{106}{9}\\[1em] \Rightarrow 11\dfrac{7}{9}\\[1em] ⇒ 3 10 + 9 20 + 2 9 + 18 31 ⇒ 3 × 6 10 × 6 + 9 × 2 20 × 2 + 2 × 9 9 × 9 + 18 × 1 31 × 1 ⇒ 18 60 + 18 40 + 18 81 + 18 31 ⇒ 18 60 + 40 + 81 + 31 ⇒ 18 212 ⇒ 9 106 ⇒ 11 9 7
Hence, 3 1 3 + 2 2 9 + 4 1 2 + 1 13 18 = 11 7 9 3\dfrac{1}{3} + 2\dfrac{2}{9} + 4\dfrac{1}{2} + 1\dfrac{13}{18} = 11\dfrac{7}{9} 3 3 1 + 2 9 2 + 4 2 1 + 1 18 13 = 11 9 7
Find the difference :
(i) 9 11 − 5 11 \dfrac{9}{11} - \dfrac{5}{11} 11 9 − 11 5
(ii) 8 5 7 − 6 7 8\dfrac{5}{7} - \dfrac{6}{7} 8 7 5 − 7 6
(iii) 3 3 8 − 1 7 8 3\dfrac{3}{8} - 1\dfrac{7}{8} 3 8 3 − 1 8 7
(iv) 7 4 − 3 4 \dfrac{7}{4} - \dfrac{3}{4} 4 7 − 4 3
Answer
(i) 9 11 − 5 11 \dfrac{9}{11} - \dfrac{5}{11} 11 9 − 11 5
⇒ 9 − 5 11 ⇒ 4 11 \Rightarrow \dfrac{9 - 5}{11}\\[1em] \Rightarrow \dfrac{4}{11} ⇒ 11 9 − 5 ⇒ 11 4
Hence, 9 11 − 5 11 = 4 11 \dfrac{9}{11} - \dfrac{5}{11} = \dfrac{4}{11} 11 9 − 11 5 = 11 4 .
(ii) 8 5 7 − 6 7 8\dfrac{5}{7} - \dfrac{6}{7} 8 7 5 − 7 6
⇒ 61 7 − 6 7 ⇒ 61 − 6 7 ⇒ 55 7 = 7 6 7 \Rightarrow \dfrac{61}{7} - \dfrac{6}{7}\\[1em] \Rightarrow \dfrac{61 - 6}{7}\\[1em] \Rightarrow \dfrac{55}{7} = 7\dfrac{6}{7} ⇒ 7 61 − 7 6 ⇒ 7 61 − 6 ⇒ 7 55 = 7 7 6
Hence, 8 5 7 − 6 7 = 7 6 7 8\dfrac{5}{7} - \dfrac{6}{7} = 7\dfrac{6}{7} 8 7 5 − 7 6 = 7 7 6 .
(iii) 3 3 8 − 1 7 8 3\dfrac{3}{8} - 1\dfrac{7}{8} 3 8 3 − 1 8 7
⇒ 27 8 − 15 8 ⇒ 27 − 15 8 ⇒ 12 8 ⇒ 3 2 = 1 1 2 \Rightarrow \dfrac{27}{8} - \dfrac{15}{8}\\[1em] \Rightarrow \dfrac{27 - 15}{8}\\[1em] \Rightarrow \dfrac{12}{8}\\[1em] \Rightarrow \dfrac{3}{2} = 1\dfrac{1}{2} ⇒ 8 27 − 8 15 ⇒ 8 27 − 15 ⇒ 8 12 ⇒ 2 3 = 1 2 1
Hence, 3 3 8 − 1 7 8 = 1 1 2 3\dfrac{3}{8} - 1\dfrac{7}{8} = 1\dfrac{1}{2} 3 8 3 − 1 8 7 = 1 2 1 .
(iv) 7 4 − 3 4 \dfrac{7}{4} - \dfrac{3}{4} 4 7 − 4 3
⇒ 7 − 3 4 ⇒ 4 4 ⇒ 1 \Rightarrow \dfrac{7 - 3}{4}\\[1em] \Rightarrow \dfrac{4}{4}\\[1em] \Rightarrow 1 ⇒ 4 7 − 3 ⇒ 4 4 ⇒ 1
Hence, 7 4 − 3 4 = 1 \dfrac{7}{4} - \dfrac{3}{4} = 1 4 7 − 4 3 = 1 .
Find the difference :
(i) 7 15 − 9 20 \dfrac{7}{15} - \dfrac{9}{20} 15 7 − 20 9
(ii) 4 1 7 − 2 1 14 4\dfrac{1}{7} - 2\dfrac{1}{14} 4 7 1 − 2 14 1
(iii) 1 7 8 − 5 12 1\dfrac{7}{8} - \dfrac{5}{12} 1 8 7 − 12 5
(iv) 5 − 2 3 4 5 - 2\dfrac{3}{4} 5 − 2 4 3
Answer
(i) 7 15 − 9 20 \dfrac{7}{15} - \dfrac{9}{20} 15 7 − 20 9
LCM of 15 and 20 = 60
⇒ 7 × 4 15 × 4 − 9 × 3 20 × 3 ⇒ 28 60 − 27 60 ⇒ 28 − 27 60 ⇒ 1 60 \Rightarrow \dfrac{7 \times 4}{15 \times 4} - \dfrac{9 \times 3}{20 \times 3}\\[1em] \Rightarrow \dfrac{28}{60} - \dfrac{27}{60}\\[1em] \Rightarrow \dfrac{28 - 27}{60}\\[1em] \Rightarrow \dfrac{1}{60}\\[1em] ⇒ 15 × 4 7 × 4 − 20 × 3 9 × 3 ⇒ 60 28 − 60 27 ⇒ 60 28 − 27 ⇒ 60 1
Hence, 7 15 − 9 20 = 1 60 \dfrac{7}{15} - \dfrac{9}{20} = \dfrac{1}{60} 15 7 − 20 9 = 60 1
(ii) 4 1 7 − 2 1 14 4\dfrac{1}{7} - 2\dfrac{1}{14} 4 7 1 − 2 14 1
LCM of 7 and 14 = 14
⇒ 29 7 − 29 14 ⇒ 29 × 2 7 × 2 − 29 × 1 14 × 1 ⇒ 58 14 − 29 14 ⇒ 58 − 29 14 ⇒ 29 14 ⇒ 2 1 14 \Rightarrow \dfrac{29}{7} - \dfrac{29}{14}\\[1em] \Rightarrow \dfrac{29 \times 2}{7 \times 2} - \dfrac{29 \times 1}{14 \times 1}\\[1em] \Rightarrow \dfrac{58}{14} - \dfrac{29}{14}\\[1em] \Rightarrow \dfrac{58 - 29}{14}\\[1em] \Rightarrow \dfrac{29}{14}\\[1em] \Rightarrow 2\dfrac{1}{14}\\[1em] ⇒ 7 29 − 14 29 ⇒ 7 × 2 29 × 2 − 14 × 1 29 × 1 ⇒ 14 58 − 14 29 ⇒ 14 58 − 29 ⇒ 14 29 ⇒ 2 14 1
Hence, 4 1 7 − 2 1 14 = 2 1 14 4\dfrac{1}{7} - 2\dfrac{1}{14} = 2\dfrac{1}{14} 4 7 1 − 2 14 1 = 2 14 1
(iii) 1 7 8 − 5 12 1\dfrac{7}{8} - \dfrac{5}{12} 1 8 7 − 12 5
LCM of 8 and 12 = 24
⇒ 15 8 − 5 12 ⇒ 15 × 3 8 × 3 − 5 × 2 12 × 2 ⇒ 45 24 − 10 24 ⇒ 45 − 10 24 ⇒ 35 24 ⇒ 1 11 24 \Rightarrow \dfrac{15}{8} - \dfrac{5}{12}\\[1em] \Rightarrow \dfrac{15 \times 3}{8 \times 3} - \dfrac{5 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{45}{24} - \dfrac{10}{24}\\[1em] \Rightarrow \dfrac{45 - 10}{24}\\[1em] \Rightarrow \dfrac{35}{24}\\[1em] \Rightarrow 1\dfrac{11}{24}\\[1em] ⇒ 8 15 − 12 5 ⇒ 8 × 3 15 × 3 − 12 × 2 5 × 2 ⇒ 24 45 − 24 10 ⇒ 24 45 − 10 ⇒ 24 35 ⇒ 1 24 11
Hence, 1 7 8 − 5 12 = 1 11 24 1\dfrac{7}{8} - \dfrac{5}{12} = 1\dfrac{11}{24} 1 8 7 − 12 5 = 1 24 11
(iv) 5 − 2 3 4 5 - 2\dfrac{3}{4} 5 − 2 4 3
⇒ 5 1 − 11 4 ⇒ 5 × 4 1 × 4 − 11 4 ⇒ 20 4 − 11 4 ⇒ 20 − 11 4 ⇒ 9 4 ⇒ 2 1 4 \Rightarrow \dfrac{5}{1} - \dfrac{11}{4}\\[1em] \Rightarrow \dfrac{5 \times 4}{1 \times 4} - \dfrac{11}{4}\\[1em] \Rightarrow \dfrac{20}{4} - \dfrac{11}{4}\\[1em] \Rightarrow \dfrac{20 - 11}{4}\\[1em] \Rightarrow \dfrac{9}{4}\\[1em] \Rightarrow 2\dfrac{1}{4}\\[1em] ⇒ 1 5 − 4 11 ⇒ 1 × 4 5 × 4 − 4 11 ⇒ 4 20 − 4 11 ⇒ 4 20 − 11 ⇒ 4 9 ⇒ 2 4 1
Hence, 5 − 2 3 4 = 2 1 4 5 - 2\dfrac{3}{4} = 2\dfrac{1}{4} 5 − 2 4 3 = 2 4 1
Find the difference :
(i) 5 1 8 − 4 1 12 5\dfrac{1}{8} - 4\dfrac{1}{12} 5 8 1 − 4 12 1
(ii) 6 1 6 − 3 7 10 6\dfrac{1}{6} - 3\dfrac{7}{10} 6 6 1 − 3 10 7
(iii) 12 − 6 5 8 12 - 6\dfrac{5}{8} 12 − 6 8 5
Answer
(i) 5 1 8 − 4 1 12 5\dfrac{1}{8} - 4\dfrac{1}{12} 5 8 1 − 4 12 1
LCM of 8 and 12 = 24
⇒ 41 8 − 49 12 ⇒ 41 × 3 8 × 3 − 49 × 2 12 × 2 ⇒ 123 24 − 98 24 ⇒ 123 − 98 24 ⇒ 25 24 ⇒ 1 1 24 \Rightarrow \dfrac{41}{8} - \dfrac{49}{12}\\[1em] \Rightarrow \dfrac{41 \times 3}{8 \times 3} - \dfrac{49 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{123}{24} - \dfrac{98}{24}\\[1em] \Rightarrow \dfrac{123 - 98}{24}\\[1em] \Rightarrow \dfrac{25}{24}\\[1em] \Rightarrow 1\dfrac{1}{24} ⇒ 8 41 − 12 49 ⇒ 8 × 3 41 × 3 − 12 × 2 49 × 2 ⇒ 24 123 − 24 98 ⇒ 24 123 − 98 ⇒ 24 25 ⇒ 1 24 1
Hence, 5 1 8 − 4 1 12 = 1 1 24 5\dfrac{1}{8} - 4\dfrac{1}{12} = 1\dfrac{1}{24} 5 8 1 − 4 12 1 = 1 24 1
(ii) 6 1 6 − 3 7 10 6\dfrac{1}{6} - 3\dfrac{7}{10} 6 6 1 − 3 10 7
LCM of 6 and 10 = 30
⇒ 37 6 − 37 10 ⇒ 37 × 5 6 × 5 − 37 × 3 10 × 3 ⇒ 185 30 − 111 30 ⇒ 185 − 111 30 ⇒ 74 30 ⇒ 37 15 ⇒ 2 7 15 \Rightarrow \dfrac{37}{6} - \dfrac{37}{10}\\[1em] \Rightarrow \dfrac{37 \times 5}{6 \times 5} - \dfrac{37 \times 3}{10 \times 3}\\[1em] \Rightarrow \dfrac{185}{30} - \dfrac{111}{30}\\[1em] \Rightarrow \dfrac{185 - 111}{30}\\[1em] \Rightarrow \dfrac{74}{30}\\[1em] \Rightarrow \dfrac{37}{15}\\[1em] \Rightarrow 2\dfrac{7}{15} ⇒ 6 37 − 10 37 ⇒ 6 × 5 37 × 5 − 10 × 3 37 × 3 ⇒ 30 185 − 30 111 ⇒ 30 185 − 111 ⇒ 30 74 ⇒ 15 37 ⇒ 2 15 7
Hence, 6 1 6 − 3 7 10 = 2 7 15 6\dfrac{1}{6} - 3\dfrac{7}{10} = 2\dfrac{7}{15} 6 6 1 − 3 10 7 = 2 15 7
(iii) 12 − 6 5 8 12 - 6\dfrac{5}{8} 12 − 6 8 5
⇒ 12 1 − 53 8 ⇒ 12 × 8 1 × 8 − 53 × 1 8 × 1 ⇒ 96 8 − 53 8 ⇒ 96 − 53 8 ⇒ 43 8 ⇒ 5 3 8 \Rightarrow \dfrac{12}{1} - \dfrac{53}{8}\\[1em] \Rightarrow \dfrac{12 \times 8}{1 \times 8} - \dfrac{53 \times 1}{8 \times 1}\\[1em] \Rightarrow \dfrac{96}{8} - \dfrac{53}{8}\\[1em] \Rightarrow \dfrac{96 - 53}{8}\\[1em] \Rightarrow \dfrac{43}{8}\\[1em] \Rightarrow 5\dfrac{3}{8} ⇒ 1 12 − 8 53 ⇒ 1 × 8 12 × 8 − 8 × 1 53 × 1 ⇒ 8 96 − 8 53 ⇒ 8 96 − 53 ⇒ 8 43 ⇒ 5 8 3
Hence, 12 − 6 5 8 = 5 3 8 12 - 6\dfrac{5}{8} = 5\dfrac{3}{8} 12 − 6 8 5 = 5 8 3
Simplify :
4 9 − 5 12 + 1 4 \dfrac{4}{9} - \dfrac{5}{12} + \dfrac{1}{4} 9 4 − 12 5 + 4 1
Answer
LCM of 9, 12 and 4 = 36
⇒ 4 × 4 9 × 4 − 5 × 3 12 × 3 + 1 × 9 4 × 9 ⇒ 16 36 − 15 36 + 9 36 ⇒ 16 − 15 + 9 36 ⇒ 16 − 6 36 ⇒ 10 36 ⇒ 5 18 \Rightarrow \dfrac{4 \times 4}{9 \times 4} - \dfrac{5 \times 3}{12 \times 3} + \dfrac{1 \times 9}{4 \times 9}\\[1em] \Rightarrow \dfrac{16}{36} - \dfrac{15}{36} + \dfrac{9}{36}\\[1em] \Rightarrow \dfrac{16 - 15 + 9}{36}\\[1em] \Rightarrow \dfrac{16 - 6}{36}\\[1em] \Rightarrow \dfrac{10}{36}\\[1em] \Rightarrow \dfrac{5}{18} ⇒ 9 × 4 4 × 4 − 12 × 3 5 × 3 + 4 × 9 1 × 9 ⇒ 36 16 − 36 15 + 36 9 ⇒ 36 16 − 15 + 9 ⇒ 36 16 − 6 ⇒ 36 10 ⇒ 18 5
Hence, 4 9 − 5 12 + 1 4 = 5 18 \dfrac{4}{9} - \dfrac{5}{12} + \dfrac{1}{4} = \dfrac{5}{18} 9 4 − 12 5 + 4 1 = 18 5 .
Simplify :
6 2 3 + 4 1 6 − 2 2 9 6\dfrac{2}{3} + 4\dfrac{1}{6} - 2\dfrac{2}{9} 6 3 2 + 4 6 1 − 2 9 2
Answer
Solving,
⇒ 6 2 3 + 4 1 6 − 2 2 9 ⇒ 20 3 + 25 6 − 20 9 ⇒ 20 × 6 3 × 6 + 25 × 3 6 × 3 − 20 × 2 9 × 2 ⇒ 120 18 + 75 18 − 40 18 ⇒ 120 + 75 − 40 18 ⇒ 195 − 40 18 ⇒ 155 18 ⇒ 8 11 18 . \Rightarrow 6\dfrac{2}{3} + 4\dfrac{1}{6} - 2\dfrac{2}{9} \\[1em] \Rightarrow \dfrac{20}{3} + \dfrac{25}{6} - \dfrac{20}{9}\\[1em] \Rightarrow \dfrac{20 \times 6}{3 \times 6} + \dfrac{25 \times 3}{6 \times 3} - \dfrac{20 \times 2}{9 \times 2}\\[1em] \Rightarrow \dfrac{120}{18} + \dfrac{75}{18} - \dfrac{40}{18}\\[1em] \Rightarrow \dfrac{120 + 75 - 40}{18}\\[1em] \Rightarrow \dfrac{195 - 40}{18}\\[1em] \Rightarrow \dfrac{155}{18}\\[1em] \Rightarrow 8\dfrac{11}{18}. ⇒ 6 3 2 + 4 6 1 − 2 9 2 ⇒ 3 20 + 6 25 − 9 20 ⇒ 3 × 6 20 × 6 + 6 × 3 25 × 3 − 9 × 2 20 × 2 ⇒ 18 120 + 18 75 − 18 40 ⇒ 18 120 + 75 − 40 ⇒ 18 195 − 40 ⇒ 18 155 ⇒ 8 18 11 .
Hence, 6 2 3 + 4 1 6 − 2 2 9 = 8 11 18 6\dfrac{2}{3} + 4\dfrac{1}{6} - 2\dfrac{2}{9} = 8\dfrac{11}{18} 6 3 2 + 4 6 1 − 2 9 2 = 8 18 11 .
Simplify :
9 − 4 1 2 − 2 1 5 9 - 4\dfrac{1}{2} - 2\dfrac{1}{5} 9 − 4 2 1 − 2 5 1
Answer
LCM of 2 and 5 = 10
⇒ 9 1 − 9 2 − 11 5 ⇒ 9 × 10 1 × 10 − 9 × 5 2 × 5 − 11 × 2 5 × 2 ⇒ 90 10 − 45 10 − 22 10 ⇒ 90 − 45 − 22 10 ⇒ 45 − 22 10 ⇒ 23 10 ⇒ 2 3 10 \Rightarrow \dfrac{9}{1} - \dfrac{9}{2} - \dfrac{11}{5}\\[1em] \Rightarrow \dfrac{9 \times 10}{1 \times 10} - \dfrac{9 \times 5}{2 \times 5} - \dfrac{11 \times 2}{5 \times 2}\\[1em] \Rightarrow \dfrac{90}{10} - \dfrac{45}{10} - \dfrac{22}{10}\\[1em] \Rightarrow \dfrac{90 - 45 - 22}{10}\\[1em] \Rightarrow \dfrac{45 - 22}{10}\\[1em] \Rightarrow \dfrac{23}{10}\\[1em] \Rightarrow 2\dfrac{3}{10}\\[1em] ⇒ 1 9 − 2 9 − 5 11 ⇒ 1 × 10 9 × 10 − 2 × 5 9 × 5 − 5 × 2 11 × 2 ⇒ 10 90 − 10 45 − 10 22 ⇒ 10 90 − 45 − 22 ⇒ 10 45 − 22 ⇒ 10 23 ⇒ 2 10 3
Hence, 9 − 4 1 2 − 2 1 5 = 2 3 10 9 - 4\dfrac{1}{2} - 2\dfrac{1}{5} = 2\dfrac{3}{10} 9 − 4 2 1 − 2 5 1 = 2 10 3 .
Simplify :
10 3 4 − 5 1 8 − 4 5 12 10\dfrac{3}{4} - 5\dfrac{1}{8} - 4\dfrac{5}{12} 10 4 3 − 5 8 1 − 4 12 5
Answer
LCM of 4, 8 and 12 = 24
⇒ 43 4 − 41 8 − 53 12 ⇒ 43 × 6 4 × 6 − 41 × 3 8 × 3 − 53 × 2 12 × 2 ⇒ 258 24 − 123 24 − 106 24 ⇒ 258 − 123 − 106 24 ⇒ 135 − 106 24 ⇒ 29 24 ⇒ 1 5 24 \Rightarrow \dfrac{43}{4} - \dfrac{41}{8} - \dfrac{53}{12}\\[1em] \Rightarrow \dfrac{43 \times 6}{4 \times 6} - \dfrac{41 \times 3}{8 \times 3} - \dfrac{53 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{258}{24} - \dfrac{123}{24} - \dfrac{106}{24}\\[1em] \Rightarrow \dfrac{258 - 123 - 106}{24}\\[1em] \Rightarrow \dfrac{135 - 106}{24}\\[1em] \Rightarrow \dfrac{29}{24}\\[1em] \Rightarrow 1\dfrac{5}{24}\\[1em] ⇒ 4 43 − 8 41 − 12 53 ⇒ 4 × 6 43 × 6 − 8 × 3 41 × 3 − 12 × 2 53 × 2 ⇒ 24 258 − 24 123 − 24 106 ⇒ 24 258 − 123 − 106 ⇒ 24 135 − 106 ⇒ 24 29 ⇒ 1 24 5
Hence, 10 3 4 − 5 1 8 − 4 5 12 = 1 5 24 10\dfrac{3}{4} - 5\dfrac{1}{8} - 4\dfrac{5}{12} = 1\dfrac{5}{24} 10 4 3 − 5 8 1 − 4 12 5 = 1 24 5 .
Simplify :
6 4 5 − 3 4 15 + 4 3 10 6\dfrac{4}{5} - 3\dfrac{4}{15} + 4\dfrac{3}{10} 6 5 4 − 3 15 4 + 4 10 3
Answer
LCM of 5, 15 and 10 = 30
⇒ 34 5 − 49 15 + 43 10 ⇒ 34 × 6 5 × 6 − 49 × 2 15 × 2 + 43 × 3 10 × 3 ⇒ 204 30 − 98 30 + 129 30 ⇒ 204 − 98 + 129 30 ⇒ 204 + 31 30 ⇒ 235 30 ⇒ 47 6 ⇒ 7 5 6 \Rightarrow \dfrac{34}{5} - \dfrac{49}{15} + \dfrac{43}{10}\\[1em] \Rightarrow \dfrac{34 \times 6}{5 \times 6} - \dfrac{49 \times 2}{15 \times 2} + \dfrac{43 \times 3}{10 \times 3}\\[1em] \Rightarrow \dfrac{204}{30} - \dfrac{98}{30} + \dfrac{129}{30}\\[1em] \Rightarrow \dfrac{204 - 98 + 129}{30}\\[1em] \Rightarrow \dfrac{204 + 31}{30}\\[1em] \Rightarrow \dfrac{235}{30}\\[1em] \Rightarrow \dfrac{47}{6}\\[1em] \Rightarrow 7\dfrac{5}{6} ⇒ 5 34 − 15 49 + 10 43 ⇒ 5 × 6 34 × 6 − 15 × 2 49 × 2 + 10 × 3 43 × 3 ⇒ 30 204 − 30 98 + 30 129 ⇒ 30 204 − 98 + 129 ⇒ 30 204 + 31 ⇒ 30 235 ⇒ 6 47 ⇒ 7 6 5
Hence, 6 4 5 − 3 4 15 + 4 3 10 = 7 5 6 6\dfrac{4}{5} - 3\dfrac{4}{15} + 4\dfrac{3}{10} = 7\dfrac{5}{6} 6 5 4 − 3 15 4 + 4 10 3 = 7 6 5 .
Simplify :
4 5 12 + 3 11 18 − 2 7 24 4\dfrac{5}{12} + 3\dfrac{11}{18} - 2\dfrac{7}{24} 4 12 5 + 3 18 11 − 2 24 7
Answer
LCM of 12, 18 and 24 = 72
⇒ 53 12 + 65 18 − 55 24 ⇒ 53 × 6 12 × 6 + 65 × 4 18 × 4 − 55 × 3 24 × 3 ⇒ 318 72 + 260 72 − 165 72 ⇒ 318 + 260 − 165 72 ⇒ 578 − 165 72 ⇒ 413 72 ⇒ 5 53 72 \Rightarrow \dfrac{53}{12} + \dfrac{65}{18} - \dfrac{55}{24}\\[1em] \Rightarrow \dfrac{53 \times 6}{12 \times 6} + \dfrac{65 \times 4}{18 \times 4} - \dfrac{55 \times 3}{24 \times 3}\\[1em] \Rightarrow \dfrac{318}{72} + \dfrac{260}{72} - \dfrac{165}{72}\\[1em] \Rightarrow \dfrac{318 + 260 - 165}{72}\\[1em] \Rightarrow \dfrac{578 - 165}{72}\\[1em] \Rightarrow \dfrac{413}{72}\\[1em] \Rightarrow 5\dfrac{53}{72} ⇒ 12 53 + 18 65 − 24 55 ⇒ 12 × 6 53 × 6 + 18 × 4 65 × 4 − 24 × 3 55 × 3 ⇒ 72 318 + 72 260 − 72 165 ⇒ 72 318 + 260 − 165 ⇒ 72 578 − 165 ⇒ 72 413 ⇒ 5 72 53
Hence, 4 5 12 + 3 11 18 − 2 7 24 = 5 53 72 4\dfrac{5}{12} + 3\dfrac{11}{18} - 2\dfrac{7}{24} = 5\dfrac{53}{72} 4 12 5 + 3 18 11 − 2 24 7 = 5 72 53 .
Subtract the sum of 9 3 4 9\dfrac{3}{4} 9 4 3 and 3 5 6 3\dfrac{5}{6} 3 6 5 from 15 7 12 15\dfrac{7}{12} 15 12 7 .
Answer
Sum of 9 3 4 9\dfrac{3}{4} 9 4 3 and 3 5 6 3\dfrac{5}{6} 3 6 5 .
LCM of 4 and 6 = 12
⇒ 39 4 + 23 6 ⇒ 39 × 3 4 × 3 + 23 × 2 6 × 2 ⇒ 117 12 + 46 12 ⇒ 117 + 46 12 ⇒ 163 12 \Rightarrow \dfrac{39}{4} + \dfrac{23}{6}\\[1em] \Rightarrow \dfrac{39 \times 3}{4 \times 3} + \dfrac{23 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{117}{12} + \dfrac{46}{12}\\[1em] \Rightarrow \dfrac{117 + 46}{12}\\[1em] \Rightarrow \dfrac{163}{12}\\[1em] ⇒ 4 39 + 6 23 ⇒ 4 × 3 39 × 3 + 6 × 2 23 × 2 ⇒ 12 117 + 12 46 ⇒ 12 117 + 46 ⇒ 12 163
Subtract 163 12 \dfrac{163}{12} 12 163 from 15 7 12 15\dfrac{7}{12} 15 12 7
⇒ 187 12 − 163 12 ⇒ 187 − 163 12 ⇒ 24 12 ⇒ 2 \Rightarrow \dfrac{187}{12} - \dfrac{163}{12}\\[1em] \Rightarrow \dfrac{187 - 163}{12}\\[1em] \Rightarrow \dfrac{24}{12}\\[1em] \Rightarrow 2 ⇒ 12 187 − 12 163 ⇒ 12 187 − 163 ⇒ 12 24 ⇒ 2
Hence, 15 7 12 − ( 9 3 4 + 3 5 6 ) = 2 15\dfrac{7}{12} - (9\dfrac{3}{4} + 3\dfrac{5}{6}) = 2 15 12 7 − ( 9 4 3 + 3 6 5 ) = 2 .
Subtract the sum of 2 5 12 2\dfrac{5}{12} 2 12 5 and 3 3 4 3\dfrac{3}{4} 3 4 3 from the sum of 7 1 3 7\dfrac{1}{3} 7 3 1 and 5 1 6 5\dfrac{1}{6} 5 6 1 .
Answer
The sum of 2 5 12 2\dfrac{5}{12} 2 12 5 and 3 3 4 3\dfrac{3}{4} 3 4 3 .
LCM of 12 and 4 = 12
⇒ 29 12 + 15 4 ⇒ 29 12 + 15 × 3 4 × 3 ⇒ 29 12 + 45 12 ⇒ 29 + 45 12 ⇒ 74 12 ⇒ 37 6 \Rightarrow \dfrac{29}{12} + \dfrac{15}{4}\\[1em] \Rightarrow \dfrac{29}{12} + \dfrac{15 \times 3}{4 \times 3}\\[1em] \Rightarrow \dfrac{29}{12} + \dfrac{45}{12}\\[1em] \Rightarrow \dfrac{29 + 45}{12}\\[1em] \Rightarrow \dfrac{74}{12}\\[1em] \Rightarrow \dfrac{37}{6}\\[1em] ⇒ 12 29 + 4 15 ⇒ 12 29 + 4 × 3 15 × 3 ⇒ 12 29 + 12 45 ⇒ 12 29 + 45 ⇒ 12 74 ⇒ 6 37
The sum of 7 1 3 7\dfrac{1}{3} 7 3 1 and 5 1 6 5\dfrac{1}{6} 5 6 1 .
LCM of 3 and 6 = 6
⇒ 22 3 + 31 6 ⇒ 22 × 2 3 × 2 + 31 6 ⇒ 44 6 + 31 6 ⇒ 44 + 31 6 ⇒ 75 6 ⇒ 25 2 \Rightarrow \dfrac{22}{3} + \dfrac{31}{6}\\[1em] \Rightarrow \dfrac{22 \times 2}{3 \times 2} + \dfrac{31}{6}\\[1em] \Rightarrow \dfrac{44}{6} + \dfrac{31}{6}\\[1em] \Rightarrow \dfrac{44 + 31}{6}\\[1em] \Rightarrow \dfrac{75}{6}\\[1em] \Rightarrow \dfrac{25}{2}\\[1em] ⇒ 3 22 + 6 31 ⇒ 3 × 2 22 × 2 + 6 31 ⇒ 6 44 + 6 31 ⇒ 6 44 + 31 ⇒ 6 75 ⇒ 2 25
Subtract 37 6 \dfrac{37}{6} 6 37 from 25 2 \dfrac{25}{2} 2 25
LCM of 6 and 2 = 6
⇒ 25 2 − 37 6 ⇒ 25 × 3 2 × 3 − 37 6 ⇒ 75 6 − 37 6 ⇒ 75 − 37 6 ⇒ 38 6 ⇒ 19 3 ⇒ 6 1 3 \Rightarrow \dfrac{25}{2} - \dfrac{37}{6}\\[1em] \Rightarrow \dfrac{25 \times 3}{2 \times 3} - \dfrac{37}{6} \\[1em] \Rightarrow \dfrac{75}{6} - \dfrac{37}{6} \\[1em] \Rightarrow \dfrac{75 - 37}{6} \\[1em] \Rightarrow \dfrac{38}{6} \\[1em] \Rightarrow \dfrac{19}{3}\\[1em] \Rightarrow 6\dfrac{1}{3}\\[1em] ⇒ 2 25 − 6 37 ⇒ 2 × 3 25 × 3 − 6 37 ⇒ 6 75 − 6 37 ⇒ 6 75 − 37 ⇒ 6 38 ⇒ 3 19 ⇒ 6 3 1
Hence, final result = 6 1 3 6\dfrac{1}{3} 6 3 1 .
What should be added to 9 4 7 9\dfrac{4}{7} 9 7 4 to get 16?
Answer
Let the number that should be added to 9 4 7 9\dfrac{4}{7} 9 7 4 be x.
⇒ 9 4 7 + x = 16 ⇒ 67 7 + x = 16 ⇒ x = 16 − 67 7 ⇒ x = 16 × 7 7 − 67 7 ⇒ x = 112 7 − 67 7 ⇒ x = 112 − 67 7 ⇒ x = 45 7 ⇒ x = 6 3 7 \Rightarrow 9\dfrac{4}{7} + x = 16\\[1em] \Rightarrow \dfrac{67}{7} + x = 16\\[1em] \Rightarrow x = 16 - \dfrac{67}{7}\\[1em] \Rightarrow x = \dfrac{16 \times 7}{7} - \dfrac{67}{7}\\[1em] \Rightarrow x = \dfrac{112}{7} - \dfrac{67}{7}\\[1em] \Rightarrow x = \dfrac{112 - 67}{7} \\[1em] \Rightarrow x = \dfrac{45}{7} \\[1em] \Rightarrow x = 6\dfrac{3}{7} ⇒ 9 7 4 + x = 16 ⇒ 7 67 + x = 16 ⇒ x = 16 − 7 67 ⇒ x = 7 16 × 7 − 7 67 ⇒ x = 7 112 − 7 67 ⇒ x = 7 112 − 67 ⇒ x = 7 45 ⇒ x = 6 7 3
Hence, the number = 6 3 7 6\dfrac{3}{7} 6 7 3 .
What must be subtracted from 9 1 6 9\dfrac{1}{6} 9 6 1 to get 6 1 9 6\dfrac{1}{9} 6 9 1 ?
Answer
Let the number that can be subtracted be x.
⇒ 9 1 6 − x = 6 1 9 ⇒ 55 6 − x = 55 9 ⇒ x = 55 6 − 55 9 \Rightarrow 9\dfrac{1}{6} - x = 6\dfrac{1}{9}\\[1em] \Rightarrow \dfrac{55}{6} - x = \dfrac{55}{9}\\[1em] \Rightarrow x = \dfrac{55}{6} - \dfrac{55}{9}\\[1em] ⇒ 9 6 1 − x = 6 9 1 ⇒ 6 55 − x = 9 55 ⇒ x = 6 55 − 9 55
LCM of 6 and 9 = 18
⇒ x = 55 × 3 6 × 3 − 55 × 2 9 × 2 ⇒ x = 165 18 − 110 18 ⇒ x = 165 − 110 18 ⇒ x = 55 18 ⇒ x = 3 1 18 \Rightarrow x = \dfrac{55 \times 3}{6 \times 3} - \dfrac{55 \times 2}{9 \times 2}\\[1em] \Rightarrow x = \dfrac{165}{18} - \dfrac{110}{18}\\[1em] \Rightarrow x = \dfrac{165 - 110}{18}\\[1em] \Rightarrow x = \dfrac{55}{18}\\[1em] \Rightarrow x = 3\dfrac{1}{18}\\[1em] ⇒ x = 6 × 3 55 × 3 − 9 × 2 55 × 2 ⇒ x = 18 165 − 18 110 ⇒ x = 18 165 − 110 ⇒ x = 18 55 ⇒ x = 3 18 1
Hence, the number = 3 1 18 3\dfrac{1}{18} 3 18 1 .
Of 17 20 \dfrac{17}{20} 20 17 and 21 25 \dfrac{21}{25} 25 21 , which is greater and by how much?
Answer
To compare the fractions 17 20 \dfrac{17}{20} 20 17 and 21 25 \dfrac{21}{25} 25 21 , we find a common denominator, which is the LCM of 20 and 25. The LCM = 100.
⇒ 17 20 − 21 25 ⇒ 17 × 5 20 × 5 − 21 × 4 25 × 4 ⇒ 85 100 − 84 100 ⇒ 85 − 84 100 ⇒ 1 100 \Rightarrow \dfrac{17}{20} - \dfrac{21}{25}\\[1em] \Rightarrow \dfrac{17 \times 5}{20 \times 5} - \dfrac{21 \times 4}{25 \times 4}\\[1em] \Rightarrow \dfrac{85}{100} - \dfrac{84}{100}\\[1em] \Rightarrow \dfrac{85 - 84}{100}\\[1em] \Rightarrow \dfrac{1}{100} ⇒ 20 17 − 25 21 ⇒ 20 × 5 17 × 5 − 25 × 4 21 × 4 ⇒ 100 85 − 100 84 ⇒ 100 85 − 84 ⇒ 100 1
Hence, 17 20 \dfrac{17}{20} 20 17 is greater by 1 100 \dfrac{1}{100} 100 1 .
The sum of two fractions is 14 5 12 14\dfrac{5}{12} 14 12 5 . If one of them is 7 2 3 7\dfrac{2}{3} 7 3 2 , find the other.
Answer
Given, the sum of two fractions = 14 5 12 14\dfrac{5}{12} 14 12 5 .
One of them = 7 2 3 7\dfrac{2}{3} 7 3 2 .
Other number
⇒ 14 5 12 − 7 2 3 ⇒ 173 12 − 23 3 \Rightarrow 14\dfrac{5}{12} - 7\dfrac{2}{3}\\[1em] \Rightarrow \dfrac{173}{12} - \dfrac{23}{3}\\[1em] ⇒ 14 12 5 − 7 3 2 ⇒ 12 173 − 3 23
LCM of 12 and 3 = 12.
⇒ 173 12 − 23 × 4 3 × 4 ⇒ 173 12 − 92 12 ⇒ 173 − 92 12 ⇒ 81 12 ⇒ 27 4 ⇒ 6 3 4 \Rightarrow \dfrac{173}{12} - \dfrac{23\times 4}{3\times 4}\\[1em] \Rightarrow \dfrac{173}{12} - \dfrac{92}{12}\\[1em] \Rightarrow \dfrac{173 - 92}{12}\\[1em] \Rightarrow \dfrac{81}{12}\\[1em] \Rightarrow \dfrac{27}{4}\\[1em] \Rightarrow 6\dfrac{3}{4} ⇒ 12 173 − 3 × 4 23 × 4 ⇒ 12 173 − 12 92 ⇒ 12 173 − 92 ⇒ 12 81 ⇒ 4 27 ⇒ 6 4 3
Hence, the other number = 6 3 4 6\dfrac{3}{4} 6 4 3 .
From a piece of wire 12 3 4 12\dfrac{3}{4} 12 4 3 m long, a small piece of length 3 5 6 3\dfrac{5}{6} 3 6 5 m has been cut off. What is the length of the remaining piece?
Answer
Given, total length of wire = 12 3 4 12\dfrac{3}{4} 12 4 3 m
Piece of wire that has been cut off = 3 5 6 3\dfrac{5}{6} 3 6 5 m
Remaining piece
⇒ 12 3 4 − 3 5 6 ⇒ 51 4 − 23 6 \Rightarrow 12\dfrac{3}{4} - 3\dfrac{5}{6}\\[1em] \Rightarrow \dfrac{51}{4} - \dfrac{23}{6}\\[1em] ⇒ 12 4 3 − 3 6 5 ⇒ 4 51 − 6 23
LCM of 4 and 6 = 12
⇒ 51 × 3 4 × 3 − 23 × 2 6 × 2 ⇒ 153 12 − 46 12 ⇒ 153 − 46 12 ⇒ 107 12 ⇒ 8 11 12 \Rightarrow \dfrac{51 \times 3}{4 \times 3} - \dfrac{23 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{153}{12} - \dfrac{46}{12}\\[1em] \Rightarrow \dfrac{153 - 46}{12}\\[1em] \Rightarrow \dfrac{107}{12}\\[1em] \Rightarrow 8\dfrac{11}{12}\\[1em] ⇒ 4 × 3 51 × 3 − 6 × 2 23 × 2 ⇒ 12 153 − 12 46 ⇒ 12 153 − 46 ⇒ 12 107 ⇒ 8 12 11
Hence, the length of the remaining piece = 8 11 12 8\dfrac{11}{12} 8 12 11 m.
Three boxes weigh 9 1 2 9\dfrac{1}{2} 9 2 1 kg, 14 1 5 14\dfrac{1}{5} 14 5 1 kg and 18 3 4 18\dfrac{3}{4} 18 4 3 kg respectively. A porter carries all the three boxes. What is the total weight carried by the porter?
Answer
Given, weight of three boxes = 9 1 2 9\dfrac{1}{2} 9 2 1 kg, 14 1 5 14\dfrac{1}{5} 14 5 1 kg and 18 3 4 18\dfrac{3}{4} 18 4 3 kg
LCM of 2, 5 and 4 = 20
Total weight
⇒ 9 1 2 + 14 1 5 + 18 3 4 ⇒ 19 2 + 71 5 + 75 4 ⇒ 19 × 10 2 × 10 + 71 × 4 5 × 4 + 75 × 5 4 × 5 ⇒ 190 20 + 284 20 + 375 20 ⇒ 190 + 284 + 375 20 ⇒ 849 20 ⇒ 42 9 20 \Rightarrow 9\dfrac{1}{2} + 14\dfrac{1}{5} + 18\dfrac{3}{4}\\[1em] \Rightarrow \dfrac{19}{2} + \dfrac{71}{5} + \dfrac{75}{4}\\[1em] \Rightarrow \dfrac{19 \times 10}{2 \times 10} + \dfrac{71 \times 4}{5 \times 4} + \dfrac{75 \times 5}{4 \times 5}\\[1em] \Rightarrow \dfrac{190}{20} + \dfrac{284}{20} + \dfrac{375}{20}\\[1em] \Rightarrow \dfrac{190 + 284 + 375}{20}\\[1em] \Rightarrow \dfrac{849}{20}\\[1em] \Rightarrow 42\dfrac{9}{20} ⇒ 9 2 1 + 14 5 1 + 18 4 3 ⇒ 2 19 + 5 71 + 4 75 ⇒ 2 × 10 19 × 10 + 5 × 4 71 × 4 + 4 × 5 75 × 5 ⇒ 20 190 + 20 284 + 20 375 ⇒ 20 190 + 284 + 375 ⇒ 20 849 ⇒ 42 20 9
Hence, the total weight carried by the porter = 42 9 20 42\dfrac{9}{20} 42 20 9 kg.
On one day, a labourer earned ₹ 125. Out of this money, he spent ₹ 68 1 2 68\dfrac{1}{2} 68 2 1 on food, ₹ 20 3 4 20\dfrac{3}{4} 20 4 3 on tea and ₹ 16 2 5 16\dfrac{2}{5} 16 5 2 on other eatables. How much does he save on that day?
Answer
Given, expenses = ₹ 68 1 2 68\dfrac{1}{2} 68 2 1 on food, ₹ 20 3 4 20\dfrac{3}{4} 20 4 3 on tea and ₹ 16 2 5 16\dfrac{2}{5} 16 5 2 on other eatables
Total
⇒ 68 1 2 + 20 3 4 + 16 2 5 ⇒ 137 2 + 83 4 + 82 5 \Rightarrow 68\dfrac{1}{2} + 20\dfrac{3}{4} + 16\dfrac{2}{5}\\[1em] \Rightarrow \dfrac{137}{2} + \dfrac{83}{4} + \dfrac{82}{5}\\[1em] ⇒ 68 2 1 + 20 4 3 + 16 5 2 ⇒ 2 137 + 4 83 + 5 82
LCM of 2, 4 and 5 = 20
⇒ 137 × 10 2 × 10 + 83 × 5 4 × 5 + 82 × 4 5 × 4 ⇒ 1370 20 + 415 20 + 328 20 ⇒ 1370 + 415 + 328 20 ⇒ 2113 20 ⇒ 105 13 20 \Rightarrow \dfrac{137 \times 10}{2 \times 10} + \dfrac{83 \times 5}{4 \times 5} + \dfrac{82 \times 4}{5 \times 4}\\[1em] \Rightarrow \dfrac{1370}{20} + \dfrac{415}{20} + \dfrac{328}{20}\\[1em] \Rightarrow \dfrac{1370 + 415 + 328}{20} \\[1em] \Rightarrow \dfrac{2113}{20} \\[1em] \Rightarrow 105\dfrac{13}{20} ⇒ 2 × 10 137 × 10 + 4 × 5 83 × 5 + 5 × 4 82 × 4 ⇒ 20 1370 + 20 415 + 20 328 ⇒ 20 1370 + 415 + 328 ⇒ 20 2113 ⇒ 105 20 13
Savings = Income − Total expenses
Savings = 125 − 2113 20 = 125 × 20 20 − 2113 20 = 2500 20 − 2113 20 = 2500 − 2113 20 = 387 20 = 19 7 20 \text{Savings }= 125 - \dfrac{2113}{20}\\[1em] = \dfrac{125 \times 20}{20} - \dfrac{2113}{20}\\[1em] = \dfrac{2500}{20} - \dfrac{2113}{20}\\[1em] = \dfrac{2500 - 2113}{20}\\[1em] = \dfrac{387}{20}\\[1em] = 19\dfrac{7}{20} Savings = 125 − 20 2113 = 20 125 × 20 − 20 2113 = 20 2500 − 20 2113 = 20 2500 − 2113 = 20 387 = 19 20 7
Hence, savings = ₹ 19 7 20 ₹19\dfrac{7}{20} ₹19 20 7 .
Find the product :
5 7 × 2 3 \dfrac{5}{7} \times \dfrac{2}{3} 7 5 × 3 2
Answer
⇒ 5 7 × 2 3 ⇒ 5 × 2 7 × 3 ⇒ 10 21 \Rightarrow \dfrac{5}{7} \times \dfrac{2}{3}\\[1em] \Rightarrow \dfrac{5 \times 2}{7 \times 3}\\[1em] \Rightarrow \dfrac{10}{21} ⇒ 7 5 × 3 2 ⇒ 7 × 3 5 × 2 ⇒ 21 10
Hence, 5 7 × 2 3 = 10 21 \dfrac{5}{7} \times \dfrac{2}{3} = \dfrac{10}{21} 7 5 × 3 2 = 21 10 .
Find the product :
3 5 × 4 9 \dfrac{3}{5} \times \dfrac{4}{9} 5 3 × 9 4
Answer
⇒ 3 5 × 4 9 ⇒ 3 × 4 5 × 9 ⇒ 12 45 ⇒ 4 15 \Rightarrow \dfrac{3}{5} \times \dfrac{4}{9}\\[1em] \Rightarrow \dfrac{3 \times 4}{5 \times 9}\\[1em] \Rightarrow \dfrac{12}{45}\\[1em] \Rightarrow \dfrac{4}{15} ⇒ 5 3 × 9 4 ⇒ 5 × 9 3 × 4 ⇒ 45 12 ⇒ 15 4
Hence, 3 5 × 4 9 = 4 15 \dfrac{3}{5} \times \dfrac{4}{9} = \dfrac{4}{15} 5 3 × 9 4 = 15 4 .
Find the product :
12 35 × 14 27 \dfrac{12}{35} \times \dfrac{14}{27} 35 12 × 27 14
Answer
⇒ 12 35 × 14 27 ⇒ 12 27 × 14 35 ⇒ 4 9 × 2 5 ⇒ 8 45 . \Rightarrow \dfrac{12}{35} \times \dfrac{14}{27}\\[1em] \Rightarrow \dfrac{12}{27} \times \dfrac{14}{35} \\[1em] \Rightarrow \dfrac{4}{9} \times \dfrac{2}{5} \\[1em] \Rightarrow \dfrac{8}{45}. ⇒ 35 12 × 27 14 ⇒ 27 12 × 35 14 ⇒ 9 4 × 5 2 ⇒ 45 8 .
Hence, 12 35 × 14 27 = 8 45 \dfrac{12}{35} \times \dfrac{14}{27} = \dfrac{8}{45} 35 12 × 27 14 = 45 8 .
Find the product :
30 51 × 17 25 \dfrac{30}{51} \times \dfrac{17}{25} 51 30 × 25 17
Answer
⇒ 30 51 × 17 25 ⇒ 30 25 × 17 51 ⇒ 6 5 × 1 3 ⇒ 2 5 . \Rightarrow \dfrac{30}{51} \times \dfrac{17}{25}\\[1em] \Rightarrow \dfrac{30}{25} \times \dfrac{17}{51} \\[1em] \Rightarrow \dfrac{6}{5} \times \dfrac{1}{3} \\[1em] \Rightarrow \dfrac{2}{5}. ⇒ 51 30 × 25 17 ⇒ 25 30 × 51 17 ⇒ 5 6 × 3 1 ⇒ 5 2 .
Hence, 30 51 × 17 25 = 2 5 \dfrac{30}{51} \times \dfrac{17}{25} = \dfrac{2}{5} 51 30 × 25 17 = 5 2 .
Find the product :
9 16 × 14 15 \dfrac{9}{16} \times \dfrac{14}{15} 16 9 × 15 14
Answer
⇒ 9 16 × 14 15 ⇒ 9 15 × 14 16 ⇒ 3 5 × 7 8 ⇒ 21 40 . \Rightarrow \dfrac{9}{16} \times \dfrac{14}{15}\\[1em] \Rightarrow \dfrac{9}{15} \times \dfrac{14}{16} \\[1em] \Rightarrow \dfrac{3}{5} \times \dfrac{7}{8} \\[1em] \Rightarrow \dfrac{21}{40}. ⇒ 16 9 × 15 14 ⇒ 15 9 × 16 14 ⇒ 5 3 × 8 7 ⇒ 40 21 .
Hence, 9 16 × 14 15 = 21 40 \dfrac{9}{16} \times \dfrac{14}{15} = \dfrac{21}{40} 16 9 × 15 14 = 40 21 .
Find the product :
2 11 27 × 18 2\dfrac{11}{27} \times 18 2 27 11 × 18
Answer
⇒ 2 11 27 × 18 ⇒ 65 27 × 18 ⇒ 65 × 18 27 ⇒ 65 × 2 3 ⇒ 130 3 ⇒ 43 1 3 . \Rightarrow 2\dfrac{11}{27} \times 18\\[1em] \Rightarrow \dfrac{65}{27} \times 18\\[1em] \Rightarrow 65 \times \dfrac{18}{27} \\[1em] \Rightarrow 65 \times \dfrac{2}{3} \\[1em] \Rightarrow \dfrac{130}{3} \\[1em] \Rightarrow 43\dfrac{1}{3}. ⇒ 2 27 11 × 18 ⇒ 27 65 × 18 ⇒ 65 × 27 18 ⇒ 65 × 3 2 ⇒ 3 130 ⇒ 43 3 1 .
Hence, 2 11 27 × 18 = 43 1 3 2\dfrac{11}{27} \times 18 = 43\dfrac{1}{3} 2 27 11 × 18 = 43 3 1 .
Find the product :
7 1 12 × 8 17 7\dfrac{1}{12} \times \dfrac{8}{17} 7 12 1 × 17 8
Answer
⇒ 7 1 12 × 8 17 ⇒ 85 12 × 8 17 ⇒ 85 17 × 8 12 ⇒ 5 × 2 3 ⇒ 10 3 ⇒ 3 1 3 . \Rightarrow 7\dfrac{1}{12} \times \dfrac{8}{17}\\[1em] \Rightarrow \dfrac{85}{12} \times \dfrac{8}{17}\\[1em] \Rightarrow \dfrac{85}{17} \times \dfrac{8}{12} \\[1em] \Rightarrow 5 \times \dfrac{2}{3} \\[1em] \Rightarrow \dfrac{10}{3}\\[1em] \Rightarrow 3\dfrac{1}{3}. ⇒ 7 12 1 × 17 8 ⇒ 12 85 × 17 8 ⇒ 17 85 × 12 8 ⇒ 5 × 3 2 ⇒ 3 10 ⇒ 3 3 1 .
Hence, 7 1 12 × 8 17 = 3 1 3 7\dfrac{1}{12} \times \dfrac{8}{17} = 3\dfrac{1}{3} 7 12 1 × 17 8 = 3 3 1 .
Find the product :
8 1 21 × 1 1 13 8\dfrac{1}{21} \times 1\dfrac{1}{13} 8 21 1 × 1 13 1
Answer
⇒ 8 1 21 × 1 1 13 ⇒ 169 21 × 14 13 ⇒ 169 13 × 14 21 ⇒ 13 × 2 3 ⇒ 26 3 ⇒ 8 2 3 . \Rightarrow 8\dfrac{1}{21} \times 1\dfrac{1}{13}\\[1em] \Rightarrow \dfrac{169}{21} \times \dfrac{14}{13}\\[1em] \Rightarrow \dfrac{169}{13} \times \dfrac{14}{21} \\[1em] \Rightarrow 13 \times \dfrac{2}{3} \\[1em] \Rightarrow \dfrac{26}{3} \\[1em] \Rightarrow 8\dfrac{2}{3}. ⇒ 8 21 1 × 1 13 1 ⇒ 21 169 × 13 14 ⇒ 13 169 × 21 14 ⇒ 13 × 3 2 ⇒ 3 26 ⇒ 8 3 2 .
Hence, 8 1 21 × 1 1 13 = 8 2 3 8\dfrac{1}{21} \times 1\dfrac{1}{13} = 8\dfrac{2}{3} 8 21 1 × 1 13 1 = 8 3 2 .
Find the product :
7 7 11 × 6 3 16 7\dfrac{7}{11} \times 6\dfrac{3}{16} 7 11 7 × 6 16 3
Answer
⇒ 7 7 11 × 6 3 16 ⇒ 84 11 × 99 16 ⇒ 84 16 × 99 11 ⇒ 21 4 × 9 ⇒ 189 4 ⇒ 47 1 4 . \Rightarrow 7\dfrac{7}{11} \times 6\dfrac{3}{16}\\[1em] \Rightarrow \dfrac{84}{11} \times \dfrac{99}{16}\\[1em] \Rightarrow \dfrac{84}{16} \times \dfrac{99}{11} \\[1em] \Rightarrow \dfrac{21}{4} \times 9 \\[1em] \Rightarrow \dfrac{189}{4} \\[1em] \Rightarrow 47\dfrac{1}{4}. ⇒ 7 11 7 × 6 16 3 ⇒ 11 84 × 16 99 ⇒ 16 84 × 11 99 ⇒ 4 21 × 9 ⇒ 4 189 ⇒ 47 4 1 .
Hence, 7 7 11 × 6 3 16 = 47 1 4 7\dfrac{7}{11} \times 6\dfrac{3}{16} = 47\dfrac{1}{4} 7 11 7 × 6 16 3 = 47 4 1 .
Find the product :
11 1 4 × 6 7 9 11\dfrac{1}{4} \times 6\dfrac{7}{9} 11 4 1 × 6 9 7
Answer
⇒ 11 1 4 × 6 7 9 ⇒ 45 4 × 61 9 ⇒ 45 9 × 61 4 ⇒ 5 × 61 4 ⇒ 305 4 ⇒ 76 1 4 . \Rightarrow 11\dfrac{1}{4} \times 6\dfrac{7}{9}\\[1em] \Rightarrow \dfrac{45}{4} \times \dfrac{61}{9}\\[1em] \Rightarrow \dfrac{45}{9} \times \dfrac{61}{4} \\[1em] \Rightarrow 5 \times \dfrac{61}{4} \\[1em] \Rightarrow \dfrac{305}{4} \\[1em] \Rightarrow 76\dfrac{1}{4}. ⇒ 11 4 1 × 6 9 7 ⇒ 4 45 × 9 61 ⇒ 9 45 × 4 61 ⇒ 5 × 4 61 ⇒ 4 305 ⇒ 76 4 1 .
Hence, 11 1 4 × 6 7 9 = 76 1 4 11\dfrac{1}{4} \times 6\dfrac{7}{9} = 76\dfrac{1}{4} 11 4 1 × 6 9 7 = 76 4 1 .
Find the product :
1 3 4 × 2 1 7 × 4 4 5 1\dfrac{3}{4} \times 2\dfrac{1}{7} \times 4\dfrac{4}{5} 1 4 3 × 2 7 1 × 4 5 4
Answer
⇒ 1 3 4 × 2 1 7 × 4 4 5 ⇒ 7 4 × 15 7 × 24 5 ⇒ 7 7 × 15 5 × 24 4 ⇒ 1 × 3 × 6 ⇒ 18. \Rightarrow 1\dfrac{3}{4} \times 2\dfrac{1}{7} \times 4\dfrac{4}{5}\\[1em] \Rightarrow \dfrac{7}{4} \times \dfrac{15}{7} \times \dfrac{24}{5}\\[1em] \Rightarrow \dfrac{7}{7} \times \dfrac{15}{5} \times \dfrac{24}{4} \\[1em] \Rightarrow 1 \times 3\times 6 \\[1em] \Rightarrow 18. ⇒ 1 4 3 × 2 7 1 × 4 5 4 ⇒ 4 7 × 7 15 × 5 24 ⇒ 7 7 × 5 15 × 4 24 ⇒ 1 × 3 × 6 ⇒ 18.
Hence, 1 3 4 × 2 1 7 × 4 4 5 = 18 1\dfrac{3}{4} \times 2\dfrac{1}{7} \times 4\dfrac{4}{5} = 18 1 4 3 × 2 7 1 × 4 5 4 = 18 .
Find the product :
3 1 6 × 2 3 4 × 2 4 11 3\dfrac{1}{6} \times 2\dfrac{3}{4} \times 2\dfrac{4}{11} 3 6 1 × 2 4 3 × 2 11 4
Answer
⇒ 3 1 6 × 2 3 4 × 2 4 11 ⇒ 19 6 × 11 4 × 26 11 ⇒ 19 6 × 11 11 × 26 4 ⇒ 19 6 × 1 × 13 2 ⇒ 247 12 ⇒ 20 7 12 . \Rightarrow 3\dfrac{1}{6} \times 2\dfrac{3}{4} \times 2\dfrac{4}{11}\\[1em] \Rightarrow \dfrac{19}{6} \times \dfrac{11}{4} \times \dfrac{26}{11}\\[1em] \Rightarrow \dfrac{19}{6} \times \dfrac{11}{11} \times \dfrac{26}{4} \\[1em] \Rightarrow \dfrac{19}{6} \times 1 \times \dfrac{13}{2} \\[1em] \Rightarrow \dfrac{247}{12} \\[1em] \Rightarrow 20\dfrac{7}{12}. ⇒ 3 6 1 × 2 4 3 × 2 11 4 ⇒ 6 19 × 4 11 × 11 26 ⇒ 6 19 × 11 11 × 4 26 ⇒ 6 19 × 1 × 2 13 ⇒ 12 247 ⇒ 20 12 7 .
Hence, 3 1 6 × 2 3 4 × 2 4 11 = 20 7 12 3\dfrac{1}{6} \times 2\dfrac{3}{4} \times 2\dfrac{4}{11} = 20\dfrac{7}{12} 3 6 1 × 2 4 3 × 2 11 4 = 20 12 7 .
Find the reciprocal of :
(i) 5 9 \dfrac{5}{9} 9 5
(ii) 7 13 \dfrac{7}{13} 13 7
(iii) 8
(iv) 1 5 \dfrac{1}{5} 5 1
(v) 3 2 5 3\dfrac{2}{5} 3 5 2
(vi) 8 1 9 8\dfrac{1}{9} 8 9 1
(vii) 5 3 8 5\dfrac{3}{8} 5 8 3
(viii) 23
Answer
The reciprocal of a non-zero fraction is a fraction obtained by swapping its numerator and denominator, so that their product is 1.
(i) 5 9 \dfrac{5}{9} 9 5
Hence, the reciprocal of 5 9 = 9 5 \dfrac{5}{9} = \dfrac{9}{5} 9 5 = 5 9 .
(ii) 7 13 \dfrac{7}{13} 13 7
Hence, the reciprocal of 7 13 = 13 7 \dfrac{7}{13} = \dfrac{13}{7} 13 7 = 7 13 .
(iii) 8 8 8
Hence, the reciprocal of 8 = 1 8 8 = \dfrac{1}{8} 8 = 8 1 .
(iv) 1 5 \dfrac{1}{5} 5 1
Hence, the reciprocal of 1 5 = 5 1 = 5 \dfrac{1}{5} = \dfrac{5}{1} = 5 5 1 = 1 5 = 5 .
(v) 3 2 5 3\dfrac{2}{5} 3 5 2
⇒ 17 5 \Rightarrow \dfrac{17}{5} ⇒ 5 17
Hence, the reciprocal of 17 5 = 5 17 \dfrac{17}{5} = \dfrac{5}{17} 5 17 = 17 5 .
(vi) 8 1 9 8\dfrac{1}{9} 8 9 1
⇒ 73 9 \Rightarrow \dfrac{73}{9} ⇒ 9 73
Hence, the reciprocal of 73 9 = 9 73 \dfrac{73}{9} = \dfrac{9}{73} 9 73 = 73 9 .
(vii) 5 3 8 5\dfrac{3}{8} 5 8 3
⇒ 43 8 \Rightarrow \dfrac{43}{8} ⇒ 8 43
Hence, the reciprocal of 43 8 = 8 43 \dfrac{43}{8} = \dfrac{8}{43} 8 43 = 43 8 .
(viii) 23
Hence, the reciprocal of 23 = 23 1 = 1 23 23 = \dfrac{23}{1} = \dfrac{1}{23} 23 = 1 23 = 23 1 .
Divide:
13 21 ÷ 2 7 \dfrac{13}{21} ÷ \dfrac{2}{7} 21 13 ÷ 7 2
Answer
⇒ 13 21 ÷ 2 7 ⇒ 13 21 × 7 2 ⇒ 13 2 × 7 21 ⇒ 13 2 × 1 3 ⇒ 13 6 ⇒ 2 1 6 . \Rightarrow \dfrac{13}{21} ÷ \dfrac{2}{7}\\[1em] \Rightarrow \dfrac{13}{21} \times \dfrac{7}{2}\\[1em] \Rightarrow \dfrac{13}{2} \times \dfrac{7}{21} \\[1em] \Rightarrow \dfrac{13}{2} \times \dfrac{1}{3} \\[1em] \Rightarrow \dfrac{13}{6} \\[1em] \Rightarrow 2\dfrac{1}{6}. ⇒ 21 13 ÷ 7 2 ⇒ 21 13 × 2 7 ⇒ 2 13 × 21 7 ⇒ 2 13 × 3 1 ⇒ 6 13 ⇒ 2 6 1 .
Hence, 13 21 ÷ 2 7 = 2 1 6 \dfrac{13}{21} ÷ \dfrac{2}{7} = 2\dfrac{1}{6} 21 13 ÷ 7 2 = 2 6 1 .
Divide:
3 1 8 ÷ 5 3\dfrac{1}{8} ÷ 5 3 8 1 ÷ 5
Answer
⇒ 3 1 8 ÷ 5 ⇒ 25 8 × 1 5 ⇒ 25 × 1 8 × 5 ⇒ 25 40 ⇒ 5 8 . \Rightarrow 3\dfrac{1}{8} ÷ 5\\[1em] \Rightarrow \dfrac{25}{8} \times \dfrac{1}{5}\\[1em] \Rightarrow \dfrac{25 \times 1}{8 \times 5}\\[1em] \Rightarrow \dfrac{25}{40}\\[1em] \Rightarrow \dfrac{5}{8}. ⇒ 3 8 1 ÷ 5 ⇒ 8 25 × 5 1 ⇒ 8 × 5 25 × 1 ⇒ 40 25 ⇒ 8 5 .
Hence, 3 1 8 ÷ 5 = 5 8 3\dfrac{1}{8} ÷ 5 = \dfrac{5}{8} 3 8 1 ÷ 5 = 8 5 .
Divide:
1 ÷ 2 3 5 1 ÷ 2\dfrac{3}{5} 1 ÷ 2 5 3
Answer
⇒ 1 ÷ 2 3 5 ⇒ 1 ÷ 13 5 ⇒ 1 × 5 13 ⇒ 5 13 . \Rightarrow 1 ÷ 2\dfrac{3}{5}\\[1em] \Rightarrow 1 ÷ \dfrac{13}{5}\\[1em] \Rightarrow 1 \times \dfrac{5}{13}\\[1em] \Rightarrow \dfrac{5}{13}. ⇒ 1 ÷ 2 5 3 ⇒ 1 ÷ 5 13 ⇒ 1 × 13 5 ⇒ 13 5 .
Hence, 1 ÷ 2 3 5 = 5 13 1 ÷ 2\dfrac{3}{5} = \dfrac{5}{13} 1 ÷ 2 5 3 = 13 5 .
Divide:
7 5 9 ÷ 34 7\dfrac{5}{9} ÷ 34 7 9 5 ÷ 34
Answer
⇒ 7 5 9 ÷ 34 ⇒ 68 9 ÷ 34 ⇒ 68 9 × 1 34 ⇒ 68 34 × 1 9 ⇒ 2 × 1 9 ⇒ 2 9 . \Rightarrow 7\dfrac{5}{9} ÷ 34\\[1em] \Rightarrow \dfrac{68}{9} ÷ 34\\[1em] \Rightarrow \dfrac{68}{9} \times \dfrac{1}{34}\\[1em] \Rightarrow \dfrac{68}{34} \times \dfrac{1}{9} \\[1em] \Rightarrow 2 \times \dfrac{1}{9} \\[1em] \Rightarrow \dfrac{2}{9}. ⇒ 7 9 5 ÷ 34 ⇒ 9 68 ÷ 34 ⇒ 9 68 × 34 1 ⇒ 34 68 × 9 1 ⇒ 2 × 9 1 ⇒ 9 2 .
Hence, 7 5 9 ÷ 34 = 2 9 7\dfrac{5}{9} ÷ 34 = \dfrac{2}{9} 7 9 5 ÷ 34 = 9 2 .
Divide:
70 ÷ 8 2 5 70 ÷ 8\dfrac{2}{5} 70 ÷ 8 5 2
Answer
Solving,
⇒ 70 ÷ 8 2 5 ⇒ 70 1 ÷ 42 5 ⇒ 70 1 × 5 42 ⇒ 70 42 × 5 ⇒ 5 3 × 5 ⇒ 25 3 ⇒ 8 1 3 . \Rightarrow 70 ÷ 8\dfrac{2}{5}\\[1em] \Rightarrow \dfrac{70}{1} ÷ \dfrac{42}{5}\\[1em] \Rightarrow \dfrac{70}{1} \times \dfrac{5}{42}\\[1em] \Rightarrow \dfrac{70}{42} \times 5 \\[1em] \Rightarrow \dfrac{5}{3} \times 5 \\[1em] \Rightarrow \dfrac{25}{3}\\[1em] \Rightarrow 8\dfrac{1}{3}. ⇒ 70 ÷ 8 5 2 ⇒ 1 70 ÷ 5 42 ⇒ 1 70 × 42 5 ⇒ 42 70 × 5 ⇒ 3 5 × 5 ⇒ 3 25 ⇒ 8 3 1 .
Hence, 70 ÷ 8 2 5 = 8 1 3 70 ÷ 8\dfrac{2}{5} = 8\dfrac{1}{3} 70 ÷ 8 5 2 = 8 3 1 .
Divide:
4 1 2 ÷ 6 1 2 4\dfrac{1}{2} ÷ 6\dfrac{1}{2} 4 2 1 ÷ 6 2 1
Answer
Solving,
⇒ 4 1 2 ÷ 6 1 2 ⇒ 9 2 ÷ 13 2 ⇒ 9 2 × 2 13 ⇒ 9 × 2 2 × 13 ⇒ 9 13 . \Rightarrow 4\dfrac{1}{2} ÷ 6\dfrac{1}{2}\\[1em] \Rightarrow \dfrac{9}{2} ÷ \dfrac{13}{2}\\[1em] \Rightarrow \dfrac{9}{2} \times \dfrac{2}{13}\\[1em] \Rightarrow \dfrac{9 \times 2}{2 \times 13}\\[1em] \Rightarrow \dfrac{9}{13}. ⇒ 4 2 1 ÷ 6 2 1 ⇒ 2 9 ÷ 2 13 ⇒ 2 9 × 13 2 ⇒ 2 × 13 9 × 2 ⇒ 13 9 .
Hence, 4 1 2 ÷ 6 1 2 = 9 13 4\dfrac{1}{2} ÷ 6\dfrac{1}{2} = \dfrac{9}{13} 4 2 1 ÷ 6 2 1 = 13 9 .
Divide:
5 7 10 ÷ 3 1 6 5\dfrac{7}{10} ÷ 3\dfrac{1}{6} 5 10 7 ÷ 3 6 1
Answer
Solving,
⇒ 5 7 10 ÷ 3 1 6 ⇒ 57 10 ÷ 19 6 ⇒ 57 10 × 6 19 ⇒ 57 19 × 6 10 ⇒ 3 × 3 5 ⇒ 9 5 ⇒ 1 4 5 . \Rightarrow 5\dfrac{7}{10} ÷ 3\dfrac{1}{6}\\[1em] \Rightarrow \dfrac{57}{10} ÷ \dfrac{19}{6}\\[1em] \Rightarrow \dfrac{57}{10} \times \dfrac{6}{19}\\[1em] \Rightarrow \dfrac{57}{19} \times \dfrac{6}{10} \\[1em] \Rightarrow 3 \times \dfrac{3}{5}\\[1em] \Rightarrow \dfrac{9}{5}\\[1em] \Rightarrow 1\dfrac{4}{5}. ⇒ 5 10 7 ÷ 3 6 1 ⇒ 10 57 ÷ 6 19 ⇒ 10 57 × 19 6 ⇒ 19 57 × 10 6 ⇒ 3 × 5 3 ⇒ 5 9 ⇒ 1 5 4 .
Hence, 5 7 10 ÷ 3 1 6 = 1 4 5 5\dfrac{7}{10} ÷ 3\dfrac{1}{6} = 1\dfrac{4}{5} 5 10 7 ÷ 3 6 1 = 1 5 4 .
Divide:
10 5 7 ÷ 1 11 14 10\dfrac{5}{7} ÷ 1\dfrac{11}{14} 10 7 5 ÷ 1 14 11
Answer
Solving,
⇒ 10 5 7 ÷ 1 11 14 ⇒ 75 7 ÷ 25 14 ⇒ 75 7 × 14 25 ⇒ 75 25 × 14 7 ⇒ 3 × 2 ⇒ 6. \Rightarrow 10\dfrac{5}{7} ÷ 1\dfrac{11}{14}\\[1em] \Rightarrow \dfrac{75}{7} ÷ \dfrac{25}{14}\\[1em] \Rightarrow \dfrac{75}{7} \times \dfrac{14}{25}\\[1em] \Rightarrow \dfrac{75}{25} \times \dfrac{14}{7}\\[1em] \Rightarrow 3 \times 2 \\[1em] \Rightarrow 6. ⇒ 10 7 5 ÷ 1 14 11 ⇒ 7 75 ÷ 14 25 ⇒ 7 75 × 25 14 ⇒ 25 75 × 7 14 ⇒ 3 × 2 ⇒ 6.
Hence, 10 5 7 ÷ 1 11 14 = 6 10\dfrac{5}{7} ÷ 1\dfrac{11}{14} = 6 10 7 5 ÷ 1 14 11 = 6 .
Divide:
15 8 9 ÷ 3 2 3 15\dfrac{8}{9} ÷ 3\dfrac{2}{3} 15 9 8 ÷ 3 3 2
Answer
Solving,
⇒ 15 8 9 ÷ 3 2 3 ⇒ 143 9 ÷ 11 3 ⇒ 143 9 × 3 11 ⇒ 143 11 × 3 9 ⇒ 13 × 1 3 ⇒ 13 3 ⇒ 4 1 3 . \Rightarrow 15\dfrac{8}{9} ÷ 3\dfrac{2}{3}\\[1em] \Rightarrow \dfrac{143}{9} ÷ \dfrac{11}{3}\\[1em] \Rightarrow \dfrac{143}{9} \times \dfrac{3}{11}\\[1em] \Rightarrow \dfrac{143}{11} \times \dfrac{3}{9} \\[1em] \Rightarrow 13 \times \dfrac{1}{3} \\[1em] \Rightarrow \dfrac{13}{3} \\[1em] \Rightarrow 4\dfrac{1}{3}. ⇒ 15 9 8 ÷ 3 3 2 ⇒ 9 143 ÷ 3 11 ⇒ 9 143 × 11 3 ⇒ 11 143 × 9 3 ⇒ 13 × 3 1 ⇒ 3 13 ⇒ 4 3 1 .
Hence, 15 8 9 ÷ 3 2 3 = 4 1 3 15\dfrac{8}{9} ÷ 3\dfrac{2}{3} = 4\dfrac{1}{3} 15 9 8 ÷ 3 3 2 = 4 3 1
Divide:
9 4 5 ÷ 3 23 25 9\dfrac{4}{5} ÷ 3\dfrac{23}{25} 9 5 4 ÷ 3 25 23
Answer
Solving,
⇒ 9 4 5 ÷ 3 23 25 ⇒ 49 5 ÷ 98 25 ⇒ 49 5 × 25 98 ⇒ 49 98 × 25 5 ⇒ 1 2 × 5 ⇒ 5 2 ⇒ 2 1 2 . \Rightarrow 9\dfrac{4}{5} ÷ 3\dfrac{23}{25}\\[1em] \Rightarrow \dfrac{49}{5} ÷ \dfrac{98}{25}\\[1em] \Rightarrow \dfrac{49}{5} \times \dfrac{25}{98}\\[1em] \Rightarrow \dfrac{49}{98} \times \dfrac{25}{5} \\[1em] \Rightarrow \dfrac{1}{2} \times 5 \\[1em] \Rightarrow \dfrac{5}{2} \\[1em] \Rightarrow 2\dfrac{1}{2}. ⇒ 9 5 4 ÷ 3 25 23 ⇒ 5 49 ÷ 25 98 ⇒ 5 49 × 98 25 ⇒ 98 49 × 5 25 ⇒ 2 1 × 5 ⇒ 2 5 ⇒ 2 2 1 .
Hence, 9 4 5 ÷ 3 23 25 = 2 1 2 9\dfrac{4}{5} ÷ 3\dfrac{23}{25} = 2\dfrac{1}{2} 9 5 4 ÷ 3 25 23 = 2 2 1 .
Divide:
2 17 38 ÷ 1 12 19 2\dfrac{17}{38} ÷ 1\dfrac{12}{19} 2 38 17 ÷ 1 19 12
Answer
Solving,
⇒ 2 17 38 ÷ 1 12 19 ⇒ 93 38 ÷ 31 19 ⇒ 93 38 × 19 31 ⇒ 93 31 × 19 38 ⇒ 3 × 1 2 ⇒ 3 2 ⇒ 1 1 2 . \Rightarrow 2\dfrac{17}{38} ÷ 1\dfrac{12}{19}\\[1em] \Rightarrow \dfrac{93}{38} ÷ \dfrac{31}{19}\\[1em] \Rightarrow \dfrac{93}{38} \times \dfrac{19}{31}\\[1em] \Rightarrow \dfrac{93}{31} \times \dfrac{19}{38}\\[1em] \Rightarrow 3 \times \dfrac{1}{2}\\[1em] \Rightarrow \dfrac{3}{2}\\[1em] \Rightarrow 1\dfrac{1}{2}. ⇒ 2 38 17 ÷ 1 19 12 ⇒ 38 93 ÷ 19 31 ⇒ 38 93 × 31 19 ⇒ 31 93 × 38 19 ⇒ 3 × 2 1 ⇒ 2 3 ⇒ 1 2 1 .
Hence, 2 17 38 ÷ 1 12 19 = 1 1 2 2\dfrac{17}{38} ÷ 1\dfrac{12}{19} = 1\dfrac{1}{2} 2 38 17 ÷ 1 19 12 = 1 2 1 .
Divide:
8 7 25 ÷ 3 1 15 8\dfrac{7}{25} ÷ 3\dfrac{1}{15} 8 25 7 ÷ 3 15 1
Answer
Solving,
⇒ 8 7 25 ÷ 3 1 15 ⇒ 207 25 ÷ 46 15 ⇒ 207 25 × 15 46 ⇒ 207 46 × 15 25 ⇒ 9 2 × 3 5 ⇒ 27 10 ⇒ 2 7 10 . \Rightarrow 8\dfrac{7}{25} ÷ 3\dfrac{1}{15}\\[1em] \Rightarrow \dfrac{207}{25} ÷ \dfrac{46}{15}\\[1em] \Rightarrow \dfrac{207}{25} \times \dfrac{15}{46}\\[1em] \Rightarrow \dfrac{207}{46} \times \dfrac{15}{25} \\[1em] \Rightarrow \dfrac{9}{2} \times \dfrac{3}{5} \\[1em] \Rightarrow \dfrac{27}{10}\\[1em] \Rightarrow 2\dfrac{7}{10}. ⇒ 8 25 7 ÷ 3 15 1 ⇒ 25 207 ÷ 15 46 ⇒ 25 207 × 46 15 ⇒ 46 207 × 25 15 ⇒ 2 9 × 5 3 ⇒ 10 27 ⇒ 2 10 7 .
Hence, 8 7 25 ÷ 3 1 15 = 2 7 10 8\dfrac{7}{25} ÷ 3\dfrac{1}{15} = 2\dfrac{7}{10} 8 25 7 ÷ 3 15 1 = 2 10 7 .
The cost of 1 litre of milk is ₹ 42 3 5 42\dfrac{3}{5} 42 5 3 . Find the cost of 12 1 2 12\dfrac{1}{2} 12 2 1 litres of milk.
Answer
Given, the cost of 1 litre of milk = ₹ 42 3 5 42\dfrac{3}{5} 42 5 3
The cost of 12 1 2 12\dfrac{1}{2} 12 2 1 litres of milk :
= ₹ 42 3 5 × 12 1 2 = ₹ 213 5 × 25 2 = ₹ 213 2 × 25 5 = ₹ 213 2 × 5 = ₹ 1065 2 = ₹ 532 1 2 . = ₹42\dfrac{3}{5} \times 12\dfrac{1}{2}\\[1em] = ₹\dfrac{213}{5} \times \dfrac{25}{2}\\[1em] = ₹\dfrac{213}{2} \times \dfrac{25}{5}\\[1em] = ₹\dfrac{213}{2} \times 5 \\[1em] = ₹\dfrac{1065}{2}\\[1em] = ₹ 532\dfrac{1}{2}. = ₹42 5 3 × 12 2 1 = ₹ 5 213 × 2 25 = ₹ 2 213 × 5 25 = ₹ 2 213 × 5 = ₹ 2 1065 = ₹532 2 1 .
Hence, the cost of 12 1 2 12\dfrac{1}{2} 12 2 1 litres of milk = ₹ 532 1 2 532\dfrac{1}{2} 532 2 1 .
The cost of 1 litre of petrol is ₹ 65 3 4 65\dfrac{3}{4} 65 4 3 . Find the cost of 36 litres of petrol.
Answer
Given, the cost of 1 litre of petrol = ₹ 65 3 4 65\dfrac{3}{4} 65 4 3
The cost of 36 litres of petrol
= ₹ 65 3 4 × 36 = ₹ 263 4 × 36 = ₹ 263 × 36 4 = ₹ 9468 4 = ₹ 2 , 367 = ₹ 65\dfrac{3}{4} \times 36\\[1em] = ₹ \dfrac{263}{4} \times 36\\[1em] = ₹ \dfrac{263 \times 36}{4} \\[1em] = ₹ \dfrac{9468}{4} \\[1em] = ₹ 2,367 = ₹65 4 3 × 36 = ₹ 4 263 × 36 = ₹ 4 263 × 36 = ₹ 4 9468 = ₹2 , 367
Hence, the cost of 36 litres of petrol = ₹ 2,367.
The cost of 3 1 2 3\dfrac{1}{2} 3 2 1 metres of cloth is ₹ 547 3 4 547\dfrac{3}{4} 547 4 3 . Find the cost of 1 metre of cloth.
Answer
Given, the cost of 3 1 2 3\dfrac{1}{2} 3 2 1 metres of cloth = ₹ 547 3 4 547\dfrac{3}{4} 547 4 3
The cost of 1 m of cloth :
= 547 3 4 ÷ 3 1 2 = 2 , 191 4 ÷ 7 2 = 2 , 191 4 × 2 7 = 2 , 191 7 × 2 4 = 313 × 1 2 = 313 2 = 156 1 2 . = 547\dfrac{3}{4} ÷ 3\dfrac{1}{2}\\[1em] = \dfrac{2,191}{4} ÷ \dfrac{7}{2}\\[1em] = \dfrac{2,191}{4} \times \dfrac{2}{7}\\[1em] = \dfrac{2,191}{7} \times \dfrac{2}{4}\\[1em] = 313 \times \dfrac{1}{2}\\[1em] = \dfrac{313}{2}\\[1em] = 156\dfrac{1}{2}. = 547 4 3 ÷ 3 2 1 = 4 2 , 191 ÷ 2 7 = 4 2 , 191 × 7 2 = 7 2 , 191 × 4 2 = 313 × 2 1 = 2 313 = 156 2 1 .
Hence, the cost of 1 metre of cloth = ₹ 156 1 2 156\dfrac{1}{2} 156 2 1 .
Tanvy cuts 54 m of cloth into pieces, each of length 3 3 8 3\dfrac{3}{8} 3 8 3 m. How many pieces does she get?
Answer
Given, total length of cloth = 54 m
Length of each piece = 3 3 8 3\dfrac{3}{8} 3 8 3 m
Let n be the number of pieces.
By formula,
Total length = Number of pieces x length of each piece
⇒ n × 3 3 8 = 54 ⇒ n × 27 8 = 54 ⇒ n = 54 ÷ 27 8 ⇒ n = 54 × 8 27 ⇒ n = 54 27 × 8 ⇒ n = 2 × 8 ⇒ n = 16. \Rightarrow n \times 3\dfrac{3}{8} = 54\\[1em] \Rightarrow n \times \dfrac{27}{8} = 54\\[1em] \Rightarrow n = 54 ÷ \dfrac{27}{8}\\[1em] \Rightarrow n = 54 \times \dfrac{8}{27}\\[1em] \Rightarrow n = \dfrac{54}{27} \times 8 \\[1em] \Rightarrow n = 2 \times 8 \\[1em] \Rightarrow n = 16. ⇒ n × 3 8 3 = 54 ⇒ n × 8 27 = 54 ⇒ n = 54 ÷ 8 27 ⇒ n = 54 × 27 8 ⇒ n = 27 54 × 8 ⇒ n = 2 × 8 ⇒ n = 16.
Hence, the number of pieces = 16.
A cord of length 126 1 2 126\dfrac{1}{2} 126 2 1 m has been cut into 46 pieces of equal length. What is the length of each piece?
Answer
Given, total length of cord = 126 1 2 126\dfrac{1}{2} 126 2 1 m
Number of pieces = 46
Let x be the length of each piece.
By formula,
Total length = Number of pieces x length of each piece
⇒ 46 × x = 126 1 2 ⇒ 46 × x = 253 2 ⇒ x = 253 2 ÷ 46 ⇒ x = 253 2 × 1 46 ⇒ x = 253 46 × 1 2 ⇒ x = 253 92 ⇒ x = 23 × 11 23 × 4 ⇒ x = 11 4 ⇒ x = 2 3 4 . \Rightarrow 46 \times x = 126\dfrac{1}{2}\\[1em] \Rightarrow 46 \times x = \dfrac{253}{2} \\[1em] \Rightarrow x = \dfrac{253}{2} ÷ 46\\[1em] \Rightarrow x = \dfrac{253}{2} \times \dfrac{1}{46} \\[1em] \Rightarrow x = \dfrac{253}{46} \times \dfrac{1}{2} \\[1em] \Rightarrow x = \dfrac{253}{92} \\[1em] \Rightarrow x = \dfrac{23 \times 11}{23 \times 4} \\[1em] \Rightarrow x = \dfrac{11}{4} \\[1em] \Rightarrow x = 2\dfrac{3}{4}. ⇒ 46 × x = 126 2 1 ⇒ 46 × x = 2 253 ⇒ x = 2 253 ÷ 46 ⇒ x = 2 253 × 46 1 ⇒ x = 46 253 × 2 1 ⇒ x = 92 253 ⇒ x = 23 × 4 23 × 11 ⇒ x = 4 11 ⇒ x = 2 4 3 .
Hence, the length of each piece = 2 3 4 2\dfrac{3}{4} 2 4 3 m.
A car travels 283 1 2 283\dfrac{1}{2} 283 2 1 km in 4 2 3 4\dfrac{2}{3} 4 3 2 hours. How far does it go in 1 hour?
Answer
Given, total distance = 283 1 2 283\dfrac{1}{2} 283 2 1 km
Total time = 4 2 3 4\dfrac{2}{3} 4 3 2 hours
Let x be the distance covered in 1 hour.
By formula,
Distance covered in 1 hour x Total time = Total distance
⇒ x × 4 2 3 = 283 1 2 ⇒ x × 14 3 = 567 2 ⇒ x = 567 2 ÷ 14 3 ⇒ x = 567 2 × 3 14 ⇒ x = 567 14 × 3 2 ⇒ x = 81 2 × 3 2 ⇒ x = 243 4 ⇒ x = 60 3 4 . \Rightarrow x \times 4\dfrac{2}{3} = 283\dfrac{1}{2}\\[1em] \Rightarrow x \times \dfrac{14}{3} = \dfrac{567}{2}\\[1em] \Rightarrow x = \dfrac{567}{2} ÷ \dfrac{14}{3}\\[1em] \Rightarrow x = \dfrac{567}{2} \times \dfrac{3}{14}\\[1em] \Rightarrow x = \dfrac{567}{14} \times \dfrac{3}{2} \\[1em] \Rightarrow x = \dfrac{81}{2} \times \dfrac{3}{2} \\[1em] \Rightarrow x = \dfrac{243}{4} \\[1em] \Rightarrow x = 60\dfrac{3}{4}. ⇒ x × 4 3 2 = 283 2 1 ⇒ x × 3 14 = 2 567 ⇒ x = 2 567 ÷ 3 14 ⇒ x = 2 567 × 14 3 ⇒ x = 14 567 × 2 3 ⇒ x = 2 81 × 2 3 ⇒ x = 4 243 ⇒ x = 60 4 3 .
Hence, distance covered in 1 hour = 60 3 4 60\dfrac{3}{4} 60 4 3 km.
The area of a rectangular plot of land is 46 2 5 46\dfrac{2}{5} 46 5 2 sq.m. If its length is 7 1 4 7\dfrac{1}{4} 7 4 1 m, find its breadth.
Answer
Given, the area of a rectangular plot of land = 46 2 5 46\dfrac{2}{5} 46 5 2 sq. m
Length of rectangular plot = 7 1 4 7\dfrac{1}{4} 7 4 1 m
Let b be the breath of the rectangular plot.
By formula, length x breadth = area
⇒ 7 1 4 × b = 46 2 5 ⇒ 29 4 × b = 232 5 ⇒ b = 232 5 ÷ 29 4 ⇒ b = 232 5 × 4 29 ⇒ b = 232 × 4 5 × 29 ⇒ b = 232 29 × 4 5 ⇒ b = 8 × 4 5 ⇒ b = 32 5 ⇒ b = 6 2 5 . \Rightarrow 7\dfrac{1}{4} \times b = 46\dfrac{2}{5}\\[1em] \Rightarrow \dfrac{29}{4} \times b = \dfrac{232}{5}\\[1em] \Rightarrow b = \dfrac{232}{5} ÷ \dfrac{29}{4}\\[1em] \Rightarrow b = \dfrac{232}{5} \times \dfrac{4}{29}\\[1em] \Rightarrow b = \dfrac{232 \times 4}{5 \times 29}\\[1em] \Rightarrow b = \dfrac{232}{29} \times \dfrac{4}{5} \\[1em] \Rightarrow b = 8 \times \dfrac{4}{5} \\[1em] \Rightarrow b = \dfrac{32}{5}\\[1em] \Rightarrow b = 6\dfrac{2}{5}. ⇒ 7 4 1 × b = 46 5 2 ⇒ 4 29 × b = 5 232 ⇒ b = 5 232 ÷ 4 29 ⇒ b = 5 232 × 29 4 ⇒ b = 5 × 29 232 × 4 ⇒ b = 29 232 × 5 4 ⇒ b = 8 × 5 4 ⇒ b = 5 32 ⇒ b = 6 5 2 .
Hence, the breadth of the rectangular plot = 6 2 5 6\dfrac{2}{5} 6 5 2 m.
The product of two fractions is 15 3 4 15\dfrac{3}{4} 15 4 3 . If one of them is 4 1 2 4\dfrac{1}{2} 4 2 1 , find the other.
Answer
Given, the product of two fractions = 15 3 4 15\dfrac{3}{4} 15 4 3
One of the fraction = 4 1 2 4\dfrac{1}{2} 4 2 1
Let x be the other fraction.
⇒ x × 4 1 2 = 15 3 4 ⇒ x = 15 3 4 ÷ 4 1 2 = 63 4 ÷ 9 2 = 63 4 × 2 9 = 63 × 2 4 × 9 = 126 36 = 7 2 = 3 1 2 . \Rightarrow x \times 4\dfrac{1}{2} = 15\dfrac{3}{4} \\[1em] \Rightarrow x = 15\dfrac{3}{4} ÷ 4\dfrac{1}{2}\\[1em] = \dfrac{63}{4} ÷ \dfrac{9}{2}\\[1em] = \dfrac{63}{4} \times \dfrac{2}{9}\\[1em] = \dfrac{63 \times 2}{4 \times 9}\\[1em] = \dfrac{126}{36}\\[1em] = \dfrac{7}{2}\\[1em] = 3\dfrac{1}{2}. ⇒ x × 4 2 1 = 15 4 3 ⇒ x = 15 4 3 ÷ 4 2 1 = 4 63 ÷ 2 9 = 4 63 × 9 2 = 4 × 9 63 × 2 = 36 126 = 2 7 = 3 2 1 .
Hence, the other fraction = 3 1 2 3\dfrac{1}{2} 3 2 1 .
Find:
(i) 1 8 \dfrac{1}{8} 8 1 of 40
(ii) 4 11 \dfrac{4}{11} 11 4 of 4 2 5 4\dfrac{2}{5} 4 5 2
(iii) 1 3 5 1\dfrac{3}{5} 1 5 3 of 6 1 4 6\dfrac{1}{4} 6 4 1
(iv) 3 4 \dfrac{3}{4} 4 3 of ₹ 1
(v) 5 8 \dfrac{5}{8} 8 5 of 1 km
(vi) 5 12 \dfrac{5}{12} 12 5 of 1 hour
Answer
(i) 1 8 \dfrac{1}{8} 8 1 of 40
⇒ 1 8 × 40 ⇒ 1 × 40 8 ⇒ 40 8 ⇒ 5 \Rightarrow \dfrac{1}{8} \times 40\\[1em] \Rightarrow \dfrac{1 \times 40}{8}\\[1em] \Rightarrow \dfrac{40}{8}\\[1em] \Rightarrow 5 ⇒ 8 1 × 40 ⇒ 8 1 × 40 ⇒ 8 40 ⇒ 5
Hence, 1 8 \dfrac{1}{8} 8 1 of 40 = 5.
(ii) 4 11 \dfrac{4}{11} 11 4 of 4 2 5 4\dfrac{2}{5} 4 5 2
⇒ 4 11 × 4 2 5 ⇒ 4 11 × 22 5 ⇒ 4 5 × 22 11 ⇒ 4 5 × 2 ⇒ 8 5 ⇒ 1 3 5 . \Rightarrow \dfrac{4}{11} \times 4\dfrac{2}{5}\\[1em] \Rightarrow \dfrac{4}{11} \times \dfrac{22}{5}\\[1em] \Rightarrow \dfrac{4}{5} \times \dfrac{22}{11}\\[1em] \Rightarrow \dfrac{4}{5} \times 2 \\[1em] \Rightarrow \dfrac{8}{5}\\[1em] \Rightarrow 1\dfrac{3}{5}. ⇒ 11 4 × 4 5 2 ⇒ 11 4 × 5 22 ⇒ 5 4 × 11 22 ⇒ 5 4 × 2 ⇒ 5 8 ⇒ 1 5 3 .
Hence, 4 11 of 4 2 5 = 1 3 5 \dfrac{4}{11} \text{ of } 4\dfrac{2}{5} = 1\dfrac{3}{5} 11 4 of 4 5 2 = 1 5 3 .
(iii) 1 3 5 1\dfrac{3}{5} 1 5 3 of 6 1 4 6\dfrac{1}{4} 6 4 1
⇒ 1 3 5 × 6 1 4 ⇒ 8 5 × 25 4 ⇒ 8 × 25 5 × 4 ⇒ 200 20 ⇒ 10. \Rightarrow 1\dfrac{3}{5} \times 6\dfrac{1}{4}\\[1em] \Rightarrow \dfrac{8}{5} \times \dfrac{25}{4}\\[1em] \Rightarrow \dfrac{8 \times 25}{5 \times 4}\\[1em] \Rightarrow \dfrac{200}{20}\\[1em] \Rightarrow 10. ⇒ 1 5 3 × 6 4 1 ⇒ 5 8 × 4 25 ⇒ 5 × 4 8 × 25 ⇒ 20 200 ⇒ 10.
Hence, 1 3 5 of 6 1 4 = 10 1\dfrac{3}{5} \text{ of } 6\dfrac{1}{4} = 10 1 5 3 of 6 4 1 = 10 .
(iv) 3 4 \dfrac{3}{4} 4 3 of ₹ 1
⇒ 3 4 × ₹ 1 ⇒ 3 4 × 100 paise ⇒ 3 × 100 4 paise ⇒ 300 4 paise ⇒ 75 paise \Rightarrow \dfrac{3}{4} \times ₹ 1\\[1em] \Rightarrow \dfrac{3}{4} \times 100 \text{ paise}\\[1em] \Rightarrow \dfrac{3 \times 100}{4}\text{ paise}\\[1em] \Rightarrow \dfrac{300}{4}\text{ paise}\\[1em] \Rightarrow 75\text{ paise} ⇒ 4 3 × ₹1 ⇒ 4 3 × 100 paise ⇒ 4 3 × 100 paise ⇒ 4 300 paise ⇒ 75 paise
Hence, 3 4 \dfrac{3}{4} 4 3 of ₹ 1 = 75 paise.
(v) 5 8 \dfrac{5}{8} 8 5 of 1 km
⇒ 5 8 × 1 km ⇒ 5 8 × 1000 m ⇒ 5 × 1000 8 m ⇒ 5000 8 m ⇒ 625 m \Rightarrow \dfrac{5}{8} \times 1\text{ km}\\[1em] \Rightarrow \dfrac{5}{8} \times 1000\text{ m}\\[1em] \Rightarrow \dfrac{5 \times 1000}{8}\text{ m}\\[1em] \Rightarrow \dfrac{5000}{8}\text{ m}\\[1em] \Rightarrow 625\text{ m}\\[1em] ⇒ 8 5 × 1 km ⇒ 8 5 × 1000 m ⇒ 8 5 × 1000 m ⇒ 8 5000 m ⇒ 625 m
Hence, 5 8 \dfrac{5}{8} 8 5 of 1 km = 625 m.
(vi) 5 12 \dfrac{5}{12} 12 5 of 1 hour
⇒ 5 12 × 1 hour ⇒ 5 12 × 60 min ⇒ 5 × 60 12 min ⇒ 300 12 min ⇒ 25 min \Rightarrow \dfrac{5}{12} \times 1 \text{ hour}\\[1em] \Rightarrow \dfrac{5}{12} \times 60 \text{ min}\\[1em] \Rightarrow \dfrac{5 \times 60}{12} \text{ min}\\[1em] \Rightarrow \dfrac{300}{12} \text{ min}\\[1em] \Rightarrow 25 \text{ min}\\[1em] ⇒ 12 5 × 1 hour ⇒ 12 5 × 60 min ⇒ 12 5 × 60 min ⇒ 12 300 min ⇒ 25 min
Hence, 5 12 \dfrac{5}{12} 12 5 of 1 hour = 25 min.
Simplify :
1 1 6 ÷ 1 5 9 × 3 1 3 1\dfrac{1}{6} ÷ 1\dfrac{5}{9} \times 3\dfrac{1}{3} 1 6 1 ÷ 1 9 5 × 3 3 1
Answer
Solving,
⇒ 1 1 6 ÷ 1 5 9 × 3 1 3 ⇒ 7 6 ÷ 14 9 × 10 3 ⇒ 7 6 × 9 14 × 10 3 ⇒ 7 14 × 9 3 × 10 6 ⇒ 1 2 × 3 × 5 3 ⇒ 5 2 ⇒ 2 1 2 . \Rightarrow 1\dfrac{1}{6} ÷ 1\dfrac{5}{9} \times 3\dfrac{1}{3}\\[1em] \Rightarrow \dfrac{7}{6} ÷ \dfrac{14}{9} \times \dfrac{10}{3}\\[1em] \Rightarrow \dfrac{7}{6} \times \dfrac{9}{14} \times \dfrac{10}{3}\\[1em] \Rightarrow \dfrac{7}{14} \times \dfrac{9}{3} \times \dfrac{10}{6}\\[1em] \Rightarrow \dfrac{1}{2} \times 3 \times \dfrac{5}{3}\\[1em] \Rightarrow \dfrac{5}{2}\\[1em] \Rightarrow 2\dfrac{1}{2}. ⇒ 1 6 1 ÷ 1 9 5 × 3 3 1 ⇒ 6 7 ÷ 9 14 × 3 10 ⇒ 6 7 × 14 9 × 3 10 ⇒ 14 7 × 3 9 × 6 10 ⇒ 2 1 × 3 × 3 5 ⇒ 2 5 ⇒ 2 2 1 .
Hence, 1 1 6 ÷ 1 5 9 × 3 1 3 = 2 1 2 1\dfrac{1}{6} ÷ 1\dfrac{5}{9} \times 3\dfrac{1}{3} = 2\dfrac{1}{2} 1 6 1 ÷ 1 9 5 × 3 3 1 = 2 2 1 .
Simplify :
1 1 3 ÷ 3 7 1\dfrac{1}{3} ÷ \dfrac{3}{7} 1 3 1 ÷ 7 3 of 2 5 8 + 1 1 9 2\dfrac{5}{8} + 1\dfrac{1}{9} 2 8 5 + 1 9 1
Answer
Solving,
⇒ 1 1 3 ÷ 3 7 of 2 5 8 + 1 1 9 ⇒ 4 3 ÷ ( 3 7 × 21 8 ) + 10 9 ⇒ 4 3 ÷ 3 × 21 7 × 8 + 10 9 ⇒ 4 3 ÷ 63 56 + 10 9 ⇒ 4 3 ÷ 9 8 + 10 9 ⇒ 4 3 × 8 9 + 10 9 ⇒ 4 × 8 3 × 9 + 10 9 ⇒ 32 27 + 10 9 ⇒ 32 27 + 10 × 3 9 × 3 ⇒ 32 27 + 30 27 ⇒ 32 + 30 27 ⇒ 62 27 ⇒ 2 8 27 \Rightarrow 1\dfrac{1}{3} ÷ \dfrac{3}{7} \text{ of } 2\dfrac{5}{8} + 1\dfrac{1}{9}\\[1em] \Rightarrow \dfrac{4}{3} ÷ \Big(\dfrac{3}{7} \times \dfrac{21}{8}\Big) + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{4}{3} ÷ \dfrac{3 \times 21}{7 \times 8} + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{4}{3} ÷ \dfrac{63}{56} + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{4}{3} ÷ \dfrac{9}{8} + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{4}{3} \times \dfrac{8}{9} + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{4 \times 8}{3 \times 9} + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{32}{27} + \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{32}{27} + \dfrac{10 \times 3}{9 \times 3}\\[1em] \Rightarrow \dfrac{32}{27} + \dfrac{30}{27}\\[1em] \Rightarrow \dfrac{32 + 30}{27}\\[1em] \Rightarrow \dfrac{62}{27}\\[1em] \Rightarrow 2\dfrac{8}{27} ⇒ 1 3 1 ÷ 7 3 of 2 8 5 + 1 9 1 ⇒ 3 4 ÷ ( 7 3 × 8 21 ) + 9 10 ⇒ 3 4 ÷ 7 × 8 3 × 21 + 9 10 ⇒ 3 4 ÷ 56 63 + 9 10 ⇒ 3 4 ÷ 8 9 + 9 10 ⇒ 3 4 × 9 8 + 9 10 ⇒ 3 × 9 4 × 8 + 9 10 ⇒ 27 32 + 9 10 ⇒ 27 32 + 9 × 3 10 × 3 ⇒ 27 32 + 27 30 ⇒ 27 32 + 30 ⇒ 27 62 ⇒ 2 27 8
Hence, 1 1 3 ÷ 3 7 1\dfrac{1}{3} ÷ \dfrac{3}{7} 1 3 1 ÷ 7 3 of 2 5 8 + 1 1 9 = 2 8 27 2\dfrac{5}{8} + 1\dfrac{1}{9} = 2\dfrac{8}{27} 2 8 5 + 1 9 1 = 2 27 8 .
Simplify :
6 1 5 ÷ 3 1 10 6\dfrac{1}{5} ÷ 3\dfrac{1}{10} 6 5 1 ÷ 3 10 1 of 2 1 2 ÷ 1 4 2\dfrac{1}{2} ÷ \dfrac{1}{4} 2 2 1 ÷ 4 1
Answer
⇒ 6 1 5 ÷ 3 1 10 of 2 1 2 ÷ 1 4 ⇒ 6 1 5 ÷ ( 31 10 × 5 2 ) ÷ 1 4 ⇒ 6 1 5 ÷ 31 × 5 10 × 2 ÷ 1 4 ⇒ 6 1 5 ÷ 155 20 ÷ 1 4 ⇒ ( 6 1 5 ÷ 31 4 ) ÷ 1 4 ⇒ ( 31 5 ÷ 31 4 ) ÷ 1 4 ⇒ ( 31 5 × 4 31 ) ÷ 1 4 ⇒ 4 5 ÷ 1 4 ⇒ 4 5 × 4 ⇒ 16 5 ⇒ 3 1 5 . \Rightarrow 6\dfrac{1}{5} ÷ 3\dfrac{1}{10} \text{ of } 2\dfrac{1}{2} ÷ \dfrac{1}{4}\\[1em] \Rightarrow 6\dfrac{1}{5} ÷ \Big(\dfrac{31}{10} \times \dfrac{5}{2}\Big) ÷ \dfrac{1}{4}\\[1em] \Rightarrow 6\dfrac{1}{5} ÷ \dfrac{31 \times 5}{10 \times 2} ÷ \dfrac{1}{4}\\[1em] \Rightarrow 6\dfrac{1}{5} ÷ \dfrac{155}{20} ÷ \dfrac{1}{4}\\[1em] \Rightarrow \Big(6\dfrac{1}{5} ÷ \dfrac{31}{4}\Big) ÷ \dfrac{1}{4}\\[1em] \Rightarrow \Big(\dfrac{31}{5} ÷ \dfrac{31}{4}\Big) ÷ \dfrac{1}{4}\\[1em] \Rightarrow \Big(\dfrac{31}{5} \times \dfrac{4}{31}\Big) ÷ \dfrac{1}{4}\\[1em] \Rightarrow \dfrac{4}{5} ÷ \dfrac{1}{4} \\[1em] \Rightarrow \dfrac{4}{5} \times 4 \\[1em] \Rightarrow \dfrac{16}{5}\\[1em] \Rightarrow 3\dfrac{1}{5}. ⇒ 6 5 1 ÷ 3 10 1 of 2 2 1 ÷ 4 1 ⇒ 6 5 1 ÷ ( 10 31 × 2 5 ) ÷ 4 1 ⇒ 6 5 1 ÷ 10 × 2 31 × 5 ÷ 4 1 ⇒ 6 5 1 ÷ 20 155 ÷ 4 1 ⇒ ( 6 5 1 ÷ 4 31 ) ÷ 4 1 ⇒ ( 5 31 ÷ 4 31 ) ÷ 4 1 ⇒ ( 5 31 × 31 4 ) ÷ 4 1 ⇒ 5 4 ÷ 4 1 ⇒ 5 4 × 4 ⇒ 5 16 ⇒ 3 5 1 .
Hence, 6 1 5 ÷ 3 1 10 6\dfrac{1}{5} ÷ 3\dfrac{1}{10} 6 5 1 ÷ 3 10 1 of 2 1 2 ÷ 1 4 = 3 1 5 2\dfrac{1}{2} ÷ \dfrac{1}{4} = 3\dfrac{1}{5} 2 2 1 ÷ 4 1 = 3 5 1 .
Simplify :
3 2 3 − 3 11 3\dfrac{2}{3} - \dfrac{3}{11} 3 3 2 − 11 3 of 2 3 4 ÷ 1 1 4 × 1 2 3 + 1 3 2\dfrac{3}{4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3} 2 4 3 ÷ 1 4 1 × 1 3 2 + 3 1
Answer
⇒ 3 2 3 − 3 11 of 2 3 4 ÷ 1 1 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 11 × 2 3 4 ÷ 1 1 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 11 × 11 4 ÷ 1 1 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 × 11 11 × 4 ÷ 1 1 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 × 11 11 × 4 ÷ 1 1 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 4 ÷ 1 1 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 4 ÷ 5 4 × 1 2 3 + 1 3 ⇒ 3 2 3 − 3 4 × 4 5 × 5 3 + 1 3 ⇒ 3 2 3 − 3 × 4 × 5 4 × 5 × 3 + 1 3 ⇒ 3 2 3 − 1 + 1 3 ⇒ 11 3 + 1 3 − 1 ⇒ 11 + 1 3 − 1 ⇒ 12 3 − 1 ⇒ 4 − 1 ⇒ 3 \Rightarrow 3\dfrac{2}{3} - \dfrac{3}{11} \text{ of } 2\dfrac{3}{4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3}{11} \times 2\dfrac{3}{4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3}{11} \times \dfrac{11}{4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3 \times 11}{11 \times 4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3 \times 11}{11 \times 4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3}{4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3}{4} ÷ \dfrac{5}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3}{4} \times \dfrac{4}{5} \times \dfrac{5}{3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - \dfrac{3 \times 4 \times 5}{4 \times 5 \times 3} + \dfrac{1}{3}\\[1em] \Rightarrow 3\dfrac{2}{3} - 1 + \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{11}{3} + \dfrac{1}{3} - 1\\[1em] \Rightarrow \dfrac{11 + 1}{3} - 1\\[1em] \Rightarrow \dfrac{12}{3} - 1\\[1em] \Rightarrow 4 - 1\\[1em] \Rightarrow 3 ⇒ 3 3 2 − 11 3 of 2 4 3 ÷ 1 4 1 × 1 3 2 + 3 1 ⇒ 3 3 2 − 11 3 × 2 4 3 ÷ 1 4 1 × 1 3 2 + 3 1 ⇒ 3 3 2 − 11 3 × 4 11 ÷ 1 4 1 × 1 3 2 + 3 1 ⇒ 3 3 2 − 11 × 4 3 × 11 ÷ 1 4 1 × 1 3 2 + 3 1 ⇒ 3 3 2 − 11 × 4 3 × 11 ÷ 1 4 1 × 1 3 2 + 3 1 ⇒ 3 3 2 − 4 3 ÷ 1 4 1 × 1 3 2 + 3 1 ⇒ 3 3 2 − 4 3 ÷ 4 5 × 1 3 2 + 3 1 ⇒ 3 3 2 − 4 3 × 5 4 × 3 5 + 3 1 ⇒ 3 3 2 − 4 × 5 × 3 3 × 4 × 5 + 3 1 ⇒ 3 3 2 − 1 + 3 1 ⇒ 3 11 + 3 1 − 1 ⇒ 3 11 + 1 − 1 ⇒ 3 12 − 1 ⇒ 4 − 1 ⇒ 3
Hence, 3 2 3 − 3 11 3\dfrac{2}{3} - \dfrac{3}{11} 3 3 2 − 11 3 of 2 3 4 ÷ 1 1 4 × 1 2 3 + 1 3 = 3 2\dfrac{3}{4} ÷ 1\dfrac{1}{4} \times 1\dfrac{2}{3} + \dfrac{1}{3} = 3 2 4 3 ÷ 1 4 1 × 1 3 2 + 3 1 = 3 .
Simplify :
2 2 7 2\dfrac{2}{7} 2 7 2 of 15 3 4 × 2 1 4 ÷ 4 7 15\dfrac{3}{4} \times 2\dfrac{1}{4} ÷ \dfrac{4}{7} 15 4 3 × 2 4 1 ÷ 7 4 of 2 5 8 2\dfrac{5}{8} 2 8 5
Answer
⇒ ( 2 2 7 of 15 3 4 ) × 2 1 4 ÷ ( 4 7 of 2 5 8 ) ⇒ 16 7 × 63 4 × 2 1 4 ÷ 4 7 × 21 8 ⇒ 16 × 63 7 × 4 × 2 1 4 ÷ 4 × 21 7 × 8 ⇒ 4 × 9 × 2 1 4 ÷ 3 2 ⇒ 36 × 2 1 4 ÷ 3 2 ⇒ 36 × 2 1 4 × 2 3 ⇒ 36 × 9 4 × 2 3 ⇒ 36 × 3 2 ⇒ 18 × 3 ⇒ 54. \Rightarrow \Big(2\dfrac{2}{7} \text{ of } 15\dfrac{3}{4}\Big) \times 2\dfrac{1}{4} ÷ \Big(\dfrac{4}{7} \text{ of } 2\dfrac{5}{8}\Big)\\[1em] \Rightarrow \dfrac{16}{7} \times \dfrac{63}{4} \times 2\dfrac{1}{4} ÷ \dfrac{4}{7} \times \dfrac{21}{8}\\[1em] \Rightarrow \dfrac{16 \times 63}{7 \times 4} \times 2\dfrac{1}{4} ÷ \dfrac{4 \times 21}{7 \times 8} \\[1em] \Rightarrow 4 \times 9 \times 2\dfrac{1}{4} ÷ \dfrac{3}{2} \\[1em] \Rightarrow 36 \times 2\dfrac{1}{4} ÷ \dfrac{3}{2} \\[1em] \Rightarrow 36 \times 2\dfrac{1}{4} \times \dfrac{2}{3} \\[1em] \Rightarrow 36 \times \dfrac{9}{4} \times \dfrac{2}{3} \\[1em] \Rightarrow 36 \times \dfrac{3}{2} \\[1em] \Rightarrow 18 \times 3 \\[1em] \Rightarrow 54. ⇒ ( 2 7 2 of 15 4 3 ) × 2 4 1 ÷ ( 7 4 of 2 8 5 ) ⇒ 7 16 × 4 63 × 2 4 1 ÷ 7 4 × 8 21 ⇒ 7 × 4 16 × 63 × 2 4 1 ÷ 7 × 8 4 × 21 ⇒ 4 × 9 × 2 4 1 ÷ 2 3 ⇒ 36 × 2 4 1 ÷ 2 3 ⇒ 36 × 2 4 1 × 3 2 ⇒ 36 × 4 9 × 3 2 ⇒ 36 × 2 3 ⇒ 18 × 3 ⇒ 54.
Hence, 2 2 7 2\dfrac{2}{7} 2 7 2 of 15 3 4 × 2 1 4 ÷ 4 7 15\dfrac{3}{4} \times 2\dfrac{1}{4} ÷ \dfrac{4}{7} 15 4 3 × 2 4 1 ÷ 7 4 of 2 5 8 = 54 2\dfrac{5}{8} = 54 2 8 5 = 54 .
Simplify :
1 ÷ 4 7 − 1 3 1 ÷ \dfrac{4}{7} - \dfrac{1}{3} 1 ÷ 7 4 − 3 1 of 3 3 4 + 1 2 ÷ 3 3\dfrac{3}{4} + \dfrac{1}{2} ÷ 3 3 4 3 + 2 1 ÷ 3
Answer
⇒ 1 ÷ 4 7 − ( 1 3 of 3 3 4 ) + 1 2 ÷ 3 ⇒ 1 ÷ 4 7 − ( 1 3 × 3 3 4 ) + 1 2 ÷ 3 ⇒ 1 ÷ 4 7 − 1 3 × 15 4 + 1 2 ÷ 3 ⇒ 1 ÷ 4 7 − 1 × 15 3 × 4 + 1 2 ÷ 3 ⇒ 1 ÷ 4 7 − 15 12 + 1 2 ÷ 3 ⇒ 1 ÷ 4 7 − 5 4 + 1 2 ÷ 3 ⇒ 1 × 7 4 − 5 4 + 1 2 × 1 3 ⇒ 7 4 − 5 4 + 1 × 1 2 × 3 ⇒ 7 4 − 5 4 + 1 6 ⇒ 7 × 3 4 × 3 − 5 × 3 4 × 3 + 1 × 2 6 × 2 ⇒ 21 12 − 15 12 + 2 12 ⇒ 21 − 15 + 2 12 ⇒ 21 − 13 12 ⇒ 8 12 ⇒ 2 3 \Rightarrow 1 ÷ \dfrac{4}{7} - \Big(\dfrac{1}{3} \text{ of } 3\dfrac{3}{4}\Big) + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \Big(\dfrac{1}{3} \times 3\dfrac{3}{4}\Big) + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{1}{3} \times \dfrac{15}{4} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{1 \times 15}{3 \times 4} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{15}{12} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 ÷ \dfrac{4}{7} - \dfrac{5}{4} + \dfrac{1}{2} ÷ 3\\[1em] \Rightarrow 1 \times \dfrac{7}{4} - \dfrac{5}{4} + \dfrac{1}{2} \times \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{7}{4} - \dfrac{5}{4} + \dfrac{1 \times 1}{2 \times 3}\\[1em] \Rightarrow \dfrac{7}{4} - \dfrac{5}{4} + \dfrac{1}{6}\\[1em] \Rightarrow \dfrac{7 \times 3}{4 \times 3} - \dfrac{5 \times 3}{4 \times 3} + \dfrac{1 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{21}{12} - \dfrac{15}{12} + \dfrac{2}{12}\\[1em] \Rightarrow \dfrac{21 - 15 + 2}{12}\\[1em] \Rightarrow \dfrac{21 - 13}{12}\\[1em] \Rightarrow \dfrac{8}{12}\\[1em] \Rightarrow \dfrac{2}{3} ⇒ 1 ÷ 7 4 − ( 3 1 of 3 4 3 ) + 2 1 ÷ 3 ⇒ 1 ÷ 7 4 − ( 3 1 × 3 4 3 ) + 2 1 ÷ 3 ⇒ 1 ÷ 7 4 − 3 1 × 4 15 + 2 1 ÷ 3 ⇒ 1 ÷ 7 4 − 3 × 4 1 × 15 + 2 1 ÷ 3 ⇒ 1 ÷ 7 4 − 12 15 + 2 1 ÷ 3 ⇒ 1 ÷ 7 4 − 4 5 + 2 1 ÷ 3 ⇒ 1 × 4 7 − 4 5 + 2 1 × 3 1 ⇒ 4 7 − 4 5 + 2 × 3 1 × 1 ⇒ 4 7 − 4 5 + 6 1 ⇒ 4 × 3 7 × 3 − 4 × 3 5 × 3 + 6 × 2 1 × 2 ⇒ 12 21 − 12 15 + 12 2 ⇒ 12 21 − 15 + 2 ⇒ 12 21 − 13 ⇒ 12 8 ⇒ 3 2
Hence, 1 ÷ 4 7 − 1 3 1 ÷ \dfrac{4}{7} - \dfrac{1}{3} 1 ÷ 7 4 − 3 1 of 3 3 4 + 1 2 ÷ 3 = 2 3 3\dfrac{3}{4} + \dfrac{1}{2} ÷ 3 = \dfrac{2}{3} 3 4 3 + 2 1 ÷ 3 = 3 2 .
Simplify :
( 2 3 + 4 9 ) \Big(\dfrac{2}{3} + \dfrac{4}{9}\Big) ( 3 2 + 9 4 ) of 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3} 5 3 ÷ 1 3 2 × 1 4 1 − 3 1
Answer
⇒ ( 2 3 + 4 9 ) of 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ ( 2 × 3 3 × 3 + 4 9 ) of 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ ( 6 9 + 4 9 ) of 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ ( 6 + 4 9 ) of 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ 10 9 × 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ 10 × 3 9 × 5 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ 30 45 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ 2 3 ÷ 1 2 3 × 1 1 4 − 1 3 ⇒ 2 3 ÷ 5 3 × 5 4 − 1 3 ⇒ 2 3 × 3 5 × 5 4 − 1 3 ⇒ 2 × 3 × 5 3 × 5 × 4 − 1 3 ⇒ 2 × 3 × 5 3 × 5 × 4 − 1 3 ⇒ 2 4 − 1 3 ⇒ 1 2 − 1 3 ⇒ 1 × 3 2 × 3 − 1 × 2 3 × 2 ⇒ 3 6 − 2 6 ⇒ 3 − 2 6 ⇒ 1 6 \Rightarrow \Big(\dfrac{2}{3} + \dfrac{4}{9}\Big) \text{ of } \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \Big(\dfrac{2 \times 3}{3 \times 3} + \dfrac{4}{9}\Big) \text{ of } \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \Big(\dfrac{6}{9} + \dfrac{4}{9}\Big) \text{ of } \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \Big(\dfrac{6 + 4}{9}\Big) \text{ of } \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{10}{9} \times \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{10 \times 3}{9 \times 5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{30}{45} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2}{3} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2}{3} ÷ \dfrac{5}{3} \times \dfrac{5}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2}{3} \times \dfrac{3}{5} \times \dfrac{5}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2 \times 3 \times 5}{3 \times 5 \times 4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2 \times \cancel{3} \times \cancel{5}}{\cancel{3} \times \cancel{5} \times 4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2}{4} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{1}{2} - \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{1 \times 3}{2 \times 3} - \dfrac{1 \times 2}{3 \times 2}\\[1em] \Rightarrow \dfrac{3}{6} - \dfrac{2}{6}\\[1em] \Rightarrow \dfrac{3 - 2}{6}\\[1em] \Rightarrow \dfrac{1}{6} ⇒ ( 3 2 + 9 4 ) of 5 3 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ ( 3 × 3 2 × 3 + 9 4 ) of 5 3 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ ( 9 6 + 9 4 ) of 5 3 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ ( 9 6 + 4 ) of 5 3 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ 9 10 × 5 3 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ 9 × 5 10 × 3 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ 45 30 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ 3 2 ÷ 1 3 2 × 1 4 1 − 3 1 ⇒ 3 2 ÷ 3 5 × 4 5 − 3 1 ⇒ 3 2 × 5 3 × 4 5 − 3 1 ⇒ 3 × 5 × 4 2 × 3 × 5 − 3 1 ⇒ 3 × 5 × 4 2 × 3 × 5 − 3 1 ⇒ 4 2 − 3 1 ⇒ 2 1 − 3 1 ⇒ 2 × 3 1 × 3 − 3 × 2 1 × 2 ⇒ 6 3 − 6 2 ⇒ 6 3 − 2 ⇒ 6 1
Hence, ( 2 3 + 4 9 ) \Big(\dfrac{2}{3} + \dfrac{4}{9}\Big) ( 3 2 + 9 4 ) of 3 5 ÷ 1 2 3 × 1 1 4 − 1 3 = 1 6 \dfrac{3}{5} ÷ 1\dfrac{2}{3} \times 1\dfrac{1}{4} - \dfrac{1}{3} = \dfrac{1}{6} 5 3 ÷ 1 3 2 × 1 4 1 − 3 1 = 6 1
Simplify :
( 14 15 ÷ 1 1 6 + 7 10 ) × 3 4 \Big(\dfrac{14}{15} ÷ 1\dfrac{1}{6} + \dfrac{7}{10}\Big) \times \dfrac{3}{4} ( 15 14 ÷ 1 6 1 + 10 7 ) × 4 3
Answer
⇒ ( 14 15 ÷ 1 1 6 + 7 10 ) × 3 4 ⇒ ( 14 15 ÷ 7 6 + 7 10 ) × 3 4 ⇒ ( 14 15 × 6 7 + 7 10 ) × 3 4 ⇒ ( 14 × 6 15 × 7 + 7 10 ) × 3 4 ⇒ ( 84 105 + 7 10 ) × 3 4 ⇒ ( 4 5 + 7 10 ) × 3 4 ⇒ ( 4 × 2 5 × 2 + 7 10 ) × 3 4 ⇒ ( 8 10 + 7 10 ) × 3 4 ⇒ ( 8 + 7 10 ) × 3 4 ⇒ 15 10 × 3 4 ⇒ 15 × 3 10 × 4 ⇒ 45 40 ⇒ 9 8 ⇒ 1 1 8 \Rightarrow \Big(\dfrac{14}{15} ÷ 1\dfrac{1}{6} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{14}{15} ÷ \dfrac{7}{6} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{14}{15} \times \dfrac{6}{7} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{14 \times 6}{15 \times 7} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{84}{105} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{4}{5} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{4 \times 2}{5 \times 2} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{8}{10} + \dfrac{7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \Big(\dfrac{8 + 7}{10}\Big) \times \dfrac{3}{4}\\[1em] \Rightarrow \dfrac{15}{10} \times \dfrac{3}{4}\\[1em] \Rightarrow \dfrac{15 \times 3}{10 \times 4}\\[1em] \Rightarrow \dfrac{45}{40}\\[1em] \Rightarrow \dfrac{9}{8}\\[1em] \Rightarrow 1\dfrac{1}{8} ⇒ ( 15 14 ÷ 1 6 1 + 10 7 ) × 4 3 ⇒ ( 15 14 ÷ 6 7 + 10 7 ) × 4 3 ⇒ ( 15 14 × 7 6 + 10 7 ) × 4 3 ⇒ ( 15 × 7 14 × 6 + 10 7 ) × 4 3 ⇒ ( 105 84 + 10 7 ) × 4 3 ⇒ ( 5 4 + 10 7 ) × 4 3 ⇒ ( 5 × 2 4 × 2 + 10 7 ) × 4 3 ⇒ ( 10 8 + 10 7 ) × 4 3 ⇒ ( 10 8 + 7 ) × 4 3 ⇒ 10 15 × 4 3 ⇒ 10 × 4 15 × 3 ⇒ 40 45 ⇒ 8 9 ⇒ 1 8 1
Hence, ( 14 15 ÷ 1 1 6 + 7 10 ) × 3 4 = 1 1 8 \Big(\dfrac{14}{15} ÷ 1\dfrac{1}{6} + \dfrac{7}{10}\Big) \times \dfrac{3}{4} = 1\dfrac{1}{8} ( 15 14 ÷ 1 6 1 + 10 7 ) × 4 3 = 1 8 1
Simplify :
1 3 ( 2 1 2 + 3 1 3 ) ÷ 2 9 ( 3 1 8 − 1 1 12 ) \dfrac{1}{3}\Big(2\dfrac{1}{2} + 3\dfrac{1}{3}\Big) ÷ \dfrac{2}{9}\Big(3\dfrac{1}{8} - 1\dfrac{1}{12}\Big) 3 1 ( 2 2 1 + 3 3 1 ) ÷ 9 2 ( 3 8 1 − 1 12 1 )
Answer
⇒ 1 3 ( 2 1 2 + 3 1 3 ) ÷ 2 9 ( 3 1 8 − 1 1 12 ) ⇒ 1 3 ( 5 2 + 10 3 ) ÷ 2 9 ( 25 8 − 13 12 ) ⇒ 1 3 ( 5 × 3 2 × 3 + 10 × 2 3 × 2 ) ÷ 2 9 ( 25 × 3 8 × 3 − 13 × 2 12 × 2 ) ⇒ 1 3 ( 15 6 + 20 6 ) ÷ 2 9 ( 75 24 − 26 24 ) ⇒ 1 3 ( 15 + 20 6 ) ÷ 2 9 ( 75 − 26 24 ) ⇒ 1 3 ( 35 6 ) ÷ 2 9 ( 49 24 ) ⇒ 35 × 1 6 × 3 ÷ 49 × 2 24 × 9 ⇒ 35 18 ÷ 98 216 ⇒ 35 18 × 216 98 ⇒ 35 98 × 216 18 ⇒ 5 14 × 12 ⇒ 60 14 ⇒ 30 7 ⇒ 4 2 7 \Rightarrow \dfrac{1}{3}\Big(2\dfrac{1}{2} + 3\dfrac{1}{3}\Big) ÷ \dfrac{2}{9}\Big(3\dfrac{1}{8} - 1\dfrac{1}{12}\Big)\\[1em] \Rightarrow \dfrac{1}{3}\Big(\dfrac{5}{2} + \dfrac{10}{3}\Big) ÷ \dfrac{2}{9}\Big(\dfrac{25}{8} - \dfrac{13}{12}\Big)\\[1em] \Rightarrow \dfrac{1}{3}\Big(\dfrac{5 \times 3}{2 \times 3} + \dfrac{10 \times 2}{3 \times 2}\Big) ÷ \dfrac{2}{9}\Big(\dfrac{25 \times 3}{8 \times 3} - \dfrac{13 \times 2}{12 \times 2}\Big)\\[1em] \Rightarrow \dfrac{1}{3}\Big(\dfrac{15}{6} + \dfrac{20}{6}\Big) ÷ \dfrac{2}{9}\Big(\dfrac{75}{24} - \dfrac{26}{24}\Big)\\[1em] \Rightarrow \dfrac{1}{3}\Big(\dfrac{15 + 20}{6}\Big) ÷ \dfrac{2}{9}\Big(\dfrac{75 - 26}{24}\Big)\\[1em] \Rightarrow \dfrac{1}{3}\Big(\dfrac{35}{6}\Big) ÷ \dfrac{2}{9}\Big(\dfrac{49}{24}\Big)\\[1em] \Rightarrow \dfrac{35 \times 1}{6 \times 3} ÷ \dfrac{49 \times 2}{24 \times 9}\\[1em] \Rightarrow \dfrac{35}{18} ÷ \dfrac{98}{216}\\[1em] \Rightarrow \dfrac{35}{18} \times \dfrac{216}{98}\\[1em] \Rightarrow \dfrac{35}{98} \times \dfrac{216}{18} \\[1em] \Rightarrow \dfrac{5}{14} \times 12 \\[1em] \Rightarrow \dfrac{60}{14}\\[1em] \Rightarrow \dfrac{30}{7} \\[1em] \Rightarrow 4\dfrac{2}{7} ⇒ 3 1 ( 2 2 1 + 3 3 1 ) ÷ 9 2 ( 3 8 1 − 1 12 1 ) ⇒ 3 1 ( 2 5 + 3 10 ) ÷ 9 2 ( 8 25 − 12 13 ) ⇒ 3 1 ( 2 × 3 5 × 3 + 3 × 2 10 × 2 ) ÷ 9 2 ( 8 × 3 25 × 3 − 12 × 2 13 × 2 ) ⇒ 3 1 ( 6 15 + 6 20 ) ÷ 9 2 ( 24 75 − 24 26 ) ⇒ 3 1 ( 6 15 + 20 ) ÷ 9 2 ( 24 75 − 26 ) ⇒ 3 1 ( 6 35 ) ÷ 9 2 ( 24 49 ) ⇒ 6 × 3 35 × 1 ÷ 24 × 9 49 × 2 ⇒ 18 35 ÷ 216 98 ⇒ 18 35 × 98 216 ⇒ 98 35 × 18 216 ⇒ 14 5 × 12 ⇒ 14 60 ⇒ 7 30 ⇒ 4 7 2
Hence, 1 3 ( 2 1 2 + 3 1 3 ) ÷ 2 9 ( 3 1 8 − 1 1 12 ) = 4 2 7 \dfrac{1}{3}\Big(2\dfrac{1}{2} + 3\dfrac{1}{3}\Big) ÷ \dfrac{2}{9}\Big(3\dfrac{1}{8} - 1\dfrac{1}{12}\Big) = 4\dfrac{2}{7} 3 1 ( 2 2 1 + 3 3 1 ) ÷ 9 2 ( 3 8 1 − 1 12 1 ) = 4 7 2 .
Simplify :
( 1 4 − 1 9 ) ÷ ( 1 2 + 1 4 ÷ 1 3 ) \Big(\dfrac{1}{4} - \dfrac{1}{9}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{1}{4} ÷ \dfrac{1}{3}\Big) ( 4 1 − 9 1 ) ÷ ( 2 1 + 4 1 ÷ 3 1 )
Answer
⇒ ( 1 4 − 1 9 ) ÷ ( 1 2 + 1 4 ÷ 1 3 ) ⇒ ( 1 × 9 4 × 9 − 1 × 4 9 × 4 ) ÷ ( 1 2 + 1 4 × 3 1 ) ⇒ ( 9 36 − 4 36 ) ÷ ( 1 2 + 1 × 3 4 × 1 ) ⇒ ( 9 − 4 36 ) ÷ ( 1 2 + 3 4 ) ⇒ ( 5 36 ) ÷ ( 1 2 + 3 4 ) ⇒ ( 5 36 ) ÷ ( 1 × 2 2 × 2 + 3 4 ) ⇒ ( 5 36 ) ÷ ( 2 4 + 3 4 ) ⇒ ( 5 36 ) ÷ ( 2 + 3 4 ) ⇒ ( 5 36 ) ÷ ( 5 4 ) ⇒ 5 36 × 4 5 ⇒ 5 × 4 36 × 5 ⇒ 4 36 ⇒ 1 9 . \Rightarrow \Big(\dfrac{1}{4} - \dfrac{1}{9}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{1}{4} ÷ \dfrac{1}{3}\Big)\\[1em] \Rightarrow \Big(\dfrac{1 \times 9}{4 \times 9} - \dfrac{1 \times 4}{9 \times 4}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{1}{4} \times \dfrac{3}{1}\Big)\\[1em] \Rightarrow \Big(\dfrac{9}{36} - \dfrac{4}{36}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{1 \times 3}{4 \times 1}\Big)\\[1em] \Rightarrow \Big(\dfrac{9 - 4}{36}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{3}{4}\Big)\\[1em] \Rightarrow \Big(\dfrac{5}{36}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{3}{4}\Big)\\[1em] \Rightarrow \Big(\dfrac{5}{36}\Big) ÷ \Big(\dfrac{1 \times 2}{2\times 2} + \dfrac{3}{4}\Big)\\[1em] \Rightarrow \Big(\dfrac{5}{36}\Big) ÷ \Big(\dfrac{2}{4} + \dfrac{3}{4}\Big)\\[1em] \Rightarrow \Big(\dfrac{5}{36}\Big) ÷ \Big(\dfrac{2 + 3}{4}\Big)\\[1em] \Rightarrow \Big(\dfrac{5}{36}\Big) ÷ \Big(\dfrac{5}{4}\Big)\\[1em] \Rightarrow \dfrac{5}{36} \times \dfrac{4}{5}\\[1em] \Rightarrow \dfrac{5 \times 4}{36 \times 5}\\[1em] \Rightarrow \dfrac{4}{36}\\[1em] \Rightarrow \dfrac{1}{9}. ⇒ ( 4 1 − 9 1 ) ÷ ( 2 1 + 4 1 ÷ 3 1 ) ⇒ ( 4 × 9 1 × 9 − 9 × 4 1 × 4 ) ÷ ( 2 1 + 4 1 × 1 3 ) ⇒ ( 36 9 − 36 4 ) ÷ ( 2 1 + 4 × 1 1 × 3 ) ⇒ ( 36 9 − 4 ) ÷ ( 2 1 + 4 3 ) ⇒ ( 36 5 ) ÷ ( 2 1 + 4 3 ) ⇒ ( 36 5 ) ÷ ( 2 × 2 1 × 2 + 4 3 ) ⇒ ( 36 5 ) ÷ ( 4 2 + 4 3 ) ⇒ ( 36 5 ) ÷ ( 4 2 + 3 ) ⇒ ( 36 5 ) ÷ ( 4 5 ) ⇒ 36 5 × 5 4 ⇒ 36 × 5 5 × 4 ⇒ 36 4 ⇒ 9 1 .
Hence, ( 1 4 − 1 9 ) ÷ ( 1 2 + 1 4 ÷ 1 3 ) = 1 9 \Big(\dfrac{1}{4} - \dfrac{1}{9}\Big) ÷ \Big(\dfrac{1}{2} + \dfrac{1}{4} ÷ \dfrac{1}{3}\Big) = \dfrac{1}{9} ( 4 1 − 9 1 ) ÷ ( 2 1 + 4 1 ÷ 3 1 ) = 9 1 .
Simplify :
3 7 8 − { 1 3 8 ÷ ( 2 4 5 − 1 7 10 ) } 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(2\dfrac{4}{5} - 1\dfrac{7}{10}\Big)\right\rbrace 3 8 7 − { 1 8 3 ÷ ( 2 5 4 − 1 10 7 ) }
Answer
⇒ 3 7 8 − { 1 3 8 ÷ ( 2 4 5 − 1 7 10 ) } ⇒ 3 7 8 − { 1 3 8 ÷ ( 14 5 − 17 10 ) } ⇒ 3 7 8 − { 1 3 8 ÷ ( 14 × 2 5 × 2 − 17 10 ) } ⇒ 3 7 8 − { 1 3 8 ÷ ( 28 10 − 17 10 ) } ⇒ 3 7 8 − { 1 3 8 ÷ ( 28 − 17 10 ) } ⇒ 3 7 8 − { 1 3 8 ÷ ( 11 10 ) } ⇒ 3 7 8 − { 11 8 ÷ 11 10 } ⇒ 3 7 8 − { 11 8 × 10 11 } ⇒ 3 7 8 − 10 8 ⇒ 31 8 − 10 8 ⇒ 31 − 10 8 ⇒ 21 8 ⇒ 2 5 8 \Rightarrow 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(2\dfrac{4}{5} - 1\dfrac{7}{10}\Big)\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(\dfrac{14}{5} - \dfrac{17}{10}\Big)\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(\dfrac{14 \times 2}{5 \times 2} - \dfrac{17}{10}\Big)\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(\dfrac{28}{10} - \dfrac{17}{10}\Big)\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(\dfrac{28 - 17}{10}\Big)\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(\dfrac{11}{10}\Big)\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace\dfrac{11}{8} \div \dfrac{11}{10}\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \left\lbrace\dfrac{11}{8} \times \dfrac{10}{11}\right\rbrace\\[1em] \Rightarrow 3\dfrac{7}{8} - \dfrac{10}{8}\\[1em] \Rightarrow \dfrac{31}{8} - \dfrac{10}{8}\\[1em] \Rightarrow \dfrac{31 - 10}{8}\\[1em] \Rightarrow \dfrac{21}{8}\\[1em] \Rightarrow 2\dfrac{5}{8} ⇒ 3 8 7 − { 1 8 3 ÷ ( 2 5 4 − 1 10 7 ) } ⇒ 3 8 7 − { 1 8 3 ÷ ( 5 14 − 10 17 ) } ⇒ 3 8 7 − { 1 8 3 ÷ ( 5 × 2 14 × 2 − 10 17 ) } ⇒ 3 8 7 − { 1 8 3 ÷ ( 10 28 − 10 17 ) } ⇒ 3 8 7 − { 1 8 3 ÷ ( 10 28 − 17 ) } ⇒ 3 8 7 − { 1 8 3 ÷ ( 10 11 ) } ⇒ 3 8 7 − { 8 11 ÷ 10 11 } ⇒ 3 8 7 − { 8 11 × 11 10 } ⇒ 3 8 7 − 8 10 ⇒ 8 31 − 8 10 ⇒ 8 31 − 10 ⇒ 8 21 ⇒ 2 8 5
Hence, 3 7 8 − { 1 3 8 ÷ ( 2 4 5 − 1 7 10 ) } = 2 5 8 3\dfrac{7}{8} - \left\lbrace1\dfrac{3}{8} \div \Big(2\dfrac{4}{5} - 1\dfrac{7}{10}\Big)\right\rbrace = 2\dfrac{5}{8} 3 8 7 − { 1 8 3 ÷ ( 2 5 4 − 1 10 7 ) } = 2 8 5 .
Simplify :
3 ÷ [ 3 × { 3 − ( 3 − 1 4 ) } ] 3 \div \Big[3\times \left\lbrace3 - \Big(3 - \dfrac{1}{4}\Big)\right\rbrace \Big] 3 ÷ [ 3 × { 3 − ( 3 − 4 1 ) } ]
Answer
⇒ 3 ÷ [ 3 × { 3 − ( 3 − 1 4 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 3 1 − 1 4 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 3 × 4 1 × 4 − 1 4 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 12 4 − 1 4 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 12 − 1 4 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 11 4 ) } ] ⇒ 3 ÷ [ 3 × { 3 1 − 11 4 } ] ⇒ 3 ÷ [ 3 × { 3 × 4 1 × 4 − 11 4 } ] ⇒ 3 ÷ [ 3 × { 12 4 − 11 4 } ] ⇒ 3 ÷ [ 3 × { 12 − 11 4 } ] ⇒ 3 ÷ [ 3 × { 1 4 } ] ⇒ 3 ÷ [ 3 × 1 4 ] ⇒ 3 ÷ 3 4 ⇒ 3 × 4 3 ⇒ 4 × 3 3 ⇒ 4 \Rightarrow 3 \div \Big[3\times \left\lbrace3 - \Big(3 - \dfrac{1}{4}\Big)\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace3 - \Big(\dfrac{3}{1} - \dfrac{1}{4}\Big)\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace3 - \Big(\dfrac{3 \times 4}{1 \times 4} - \dfrac{1}{4}\Big)\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace3 - \Big(\dfrac{12}{4} - \dfrac{1}{4}\Big)\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace3 - \Big(\dfrac{12 - 1}{4}\Big)\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace3 - \Big(\dfrac{11}{4}\Big)\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace\dfrac{3}{1} - \dfrac{11}{4}\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace\dfrac{3 \times 4}{1 \times 4} - \dfrac{11}{4}\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace\dfrac{12}{4} - \dfrac{11}{4}\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace\dfrac{12 - 11}{4}\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[3\times \left\lbrace\dfrac{1}{4}\right\rbrace \Big]\\[1em] \Rightarrow 3 \div \Big[\dfrac{3 \times 1}{4} \Big]\\[1em] \Rightarrow 3 \div \dfrac{3}{4}\\[1em] \Rightarrow 3 \times \dfrac{4}{3}\\[1em] \Rightarrow \dfrac{4 \times 3}{3}\\[1em] \Rightarrow 4 ⇒ 3 ÷ [ 3 × { 3 − ( 3 − 4 1 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 1 3 − 4 1 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 1 × 4 3 × 4 − 4 1 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 4 12 − 4 1 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 4 12 − 1 ) } ] ⇒ 3 ÷ [ 3 × { 3 − ( 4 11 ) } ] ⇒ 3 ÷ [ 3 × { 1 3 − 4 11 } ] ⇒ 3 ÷ [ 3 × { 1 × 4 3 × 4 − 4 11 } ] ⇒ 3 ÷ [ 3 × { 4 12 − 4 11 } ] ⇒ 3 ÷ [ 3 × { 4 12 − 11 } ] ⇒ 3 ÷ [ 3 × { 4 1 } ] ⇒ 3 ÷ [ 4 3 × 1 ] ⇒ 3 ÷ 4 3 ⇒ 3 × 3 4 ⇒ 3 4 × 3 ⇒ 4
Hence, 3 ÷ [ 3 × { 3 − ( 3 − 1 4 ) } ] = 4 3 \div \Big[3\times \left\lbrace3 - \Big(3 - \dfrac{1}{4}\Big)\right\rbrace \Big] = 4 3 ÷ [ 3 × { 3 − ( 3 − 4 1 ) } ] = 4 .
Simplify :
5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × ( 7 10 − 3 5 ) } ] 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \Big(\dfrac{7}{10} - \dfrac{3}{5}\Big)\right\rbrace\Big] 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × ( 10 7 − 5 3 ) } ]
Answer
⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × ( 7 10 − 3 5 ) } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × ( 7 10 − 3 × 2 5 × 2 ) } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × ( 7 10 − 6 10 ) } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × ( 7 − 6 10 ) } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × 1 10 } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 × 1 2 × 10 } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 20 } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 3 × 5 4 × 5 − 1 20 } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 15 20 − 1 20 } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 15 − 1 20 } ] ⇒ 5 1 3 − [ 2 1 3 ÷ { 14 20 } ] ⇒ 5 1 3 − [ 7 3 ÷ 14 20 ] ⇒ 5 1 3 − [ 7 3 × 20 14 ] ⇒ 5 1 3 − [ 7 × 20 3 × 14 ] ⇒ 5 1 3 − [ 140 42 ] ⇒ 16 3 − 10 3 ⇒ 16 − 10 3 ⇒ 6 3 ⇒ 2 \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \Big(\dfrac{7}{10} - \dfrac{3}{5}\Big)\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \Big(\dfrac{7}{10} - \dfrac{3 \times 2}{5 \times 2}\Big)\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \Big(\dfrac{7}{10} - \dfrac{6}{10}\Big)\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \Big(\dfrac{7 - 6}{10}\Big)\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \dfrac{1}{10}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1 \times 1}{2 \times 10}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{20}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3 \times 5}{4 \times 5} - \dfrac{1}{20}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{15}{20} - \dfrac{1}{20}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{15 - 1}{20}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{14}{20}\right\rbrace\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[\dfrac{7}{3} \div \dfrac{14}{20}\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[\dfrac{7}{3} \times \dfrac{20}{14}\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[\dfrac{7 \times 20}{3 \times 14}\Big]\\[1em] \Rightarrow 5\dfrac{1}{3} - \Big[\dfrac{140}{42}\Big]\\[1em] \Rightarrow \dfrac{16}{3} - \dfrac{10}{3}\\[1em] \Rightarrow \dfrac{16 - 10}{3}\\[1em] \Rightarrow \dfrac{6}{3}\\[1em] \Rightarrow 2 ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × ( 10 7 − 5 3 ) } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × ( 10 7 − 5 × 2 3 × 2 ) } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × ( 10 7 − 10 6 ) } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × ( 10 7 − 6 ) } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × 10 1 } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 × 10 1 × 1 } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 3 − 20 1 } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 4 × 5 3 × 5 − 20 1 } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 20 15 − 20 1 } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 20 15 − 1 } ] ⇒ 5 3 1 − [ 2 3 1 ÷ { 20 14 } ] ⇒ 5 3 1 − [ 3 7 ÷ 20 14 ] ⇒ 5 3 1 − [ 3 7 × 14 20 ] ⇒ 5 3 1 − [ 3 × 14 7 × 20 ] ⇒ 5 3 1 − [ 42 140 ] ⇒ 3 16 − 3 10 ⇒ 3 16 − 10 ⇒ 3 6 ⇒ 2
Hence, 5 1 3 − [ 2 1 3 ÷ { 3 4 − 1 2 × ( 7 10 − 3 5 ) } ] = 2 5\dfrac{1}{3} - \Big[2\dfrac{1}{3} \div \left\lbrace\dfrac{3}{4} - \dfrac{1}{2} \times \Big(\dfrac{7}{10} - \dfrac{3}{5}\Big)\right\rbrace\Big] = 2 5 3 1 − [ 2 3 1 ÷ { 4 3 − 2 1 × ( 10 7 − 5 3 ) } ] = 2 .
A man earns ₹ 18,720 per month and spends 5 6 \dfrac{5}{6} 6 5 of his income. Find his monthly
(i) expenditure
(ii) saving.
Answer
(i) Given, a man earns = ₹ 18,720 per month
Expenditure = 5 6 of his income = 5 6 × 18720 = 5 × 18720 6 = 5 × 3120 = 15 , 600. \text{Expenditure }= \dfrac{5}{6} \text{ of his income}\\[1em] = \dfrac{5}{6} \times 18720\\[1em] = \dfrac{5 \times 18720}{6}\\[1em] = 5 \times 3120\\[1em] = 15,600. Expenditure = 6 5 of his income = 6 5 × 18720 = 6 5 × 18720 = 5 × 3120 = 15 , 600.
Hence, expenditure = ₹ 15,600.
(ii) Saving = Income - Expenditure
= 18,720 - 15,600
= ₹ 3,120.
Hence, saving = ₹ 3,120.
A water tank can hold 56 1 4 56\dfrac{1}{4} 56 4 1 litres of water. How much water is contained in the tank when it is 8 15 \dfrac{8}{15} 15 8 full?
Answer
Given,
Total capacity of tank = 56 1 4 56\dfrac{1}{4} 56 4 1 = 225 4 \dfrac{225}{4} 4 225 litres
Fraction full = 8 15 \dfrac{8}{15} 15 8
Water in the tank = 8 15 × 225 4 = 8 × 225 15 × 4 = 1800 60 = 30. \text{Water in the tank }= \dfrac{8}{15} \times \dfrac{225}{4}\\[1em] = \dfrac{8 \times 225}{15 \times 4}\\[1em] = \dfrac{1800}{60}\\[1em] = 30. Water in the tank = 15 8 × 4 225 = 15 × 4 8 × 225 = 60 1800 = 30.
Hence, water in the tank = 30 litres.
After reading 5 8 \dfrac{5}{8} 8 5 of a book, 168 pages are left. How many pages are there in all in the book?
Answer
Let the total number of pages be x.
Given, number of pages read = 5 8 \dfrac{5}{8} 8 5 x
Pages are left = 168
Number of pages left
⇒ 1 x − 5 8 x = 168 ⇒ 8 x 8 − 5 x 8 = 168 ⇒ 8 x − 5 x 8 = 168 ⇒ 3 x 8 = 168 ⇒ x = 168 × 8 3 ⇒ x = 1344 3 ⇒ x = 448 \Rightarrow 1x - \dfrac{5}{8}x = 168\\[1em] \Rightarrow \dfrac{8x}{8} - \dfrac{5x}{8} = 168\\[1em] \Rightarrow \dfrac{8x - 5x}{8} = 168\\[1em] \Rightarrow \dfrac{3x}{8} = 168\\[1em] \Rightarrow x = \dfrac{168 \times 8}{3}\\[1em] \Rightarrow x = \dfrac{1344}{3}\\[1em] \Rightarrow x = 448 ⇒ 1 x − 8 5 x = 168 ⇒ 8 8 x − 8 5 x = 168 ⇒ 8 8 x − 5 x = 168 ⇒ 8 3 x = 168 ⇒ x = 3 168 × 8 ⇒ x = 3 1344 ⇒ x = 448
Hence, total number of pages = 448.
2 3 \dfrac{2}{3} 3 2 of the students in a class are boys and the rest are 17 girls.
(i) How many boys are there in the class?
(ii) What is the total strength of the class?
Answer
(i) Given,
Number of boys in a class = 2 3 \dfrac{2}{3} 3 2 of the students
Number of girls in a class = 17
Let the number of the students in the class be x.
Number of girls = Total students - number of boys
⇒ x − 2 3 x = 17 ⇒ 3 3 x − 2 3 x = 17 ⇒ 3 − 2 3 x = 17 ⇒ 1 3 x = 17 ⇒ x = 17 × 3 ⇒ x = 51 \Rightarrow x - \dfrac{2}{3}x = 17\\[1em] \Rightarrow \dfrac{3}{3}x - \dfrac{2}{3}x = 17\\[1em] \Rightarrow \dfrac{3 - 2}{3}x = 17\\[1em] \Rightarrow \dfrac{1}{3}x = 17\\[1em] \Rightarrow x = 17\times 3\\[1em] \Rightarrow x = 51 ⇒ x − 3 2 x = 17 ⇒ 3 3 x − 3 2 x = 17 ⇒ 3 3 − 2 x = 17 ⇒ 3 1 x = 17 ⇒ x = 17 × 3 ⇒ x = 51
Number of boys = 2 3 × 51 = 2 × 51 3 = 102 3 = 34 \dfrac{2}{3} \times 51 = \dfrac{2 \times 51}{3} = \dfrac{102}{3} = 34 3 2 × 51 = 3 2 × 51 = 3 102 = 34
Hence, number of boys in the class = 34.
(ii) Hence, number of students in the class = 51.
A man earns ₹ 25,440 per month. He spends 1 4 \dfrac{1}{4} 4 1 of it on house rent, 3 8 \dfrac{3}{8} 8 3 on food and clothes, 1 10 \dfrac{1}{10} 10 1 on insurance and 1 5 \dfrac{1}{5} 5 1 on other items. The rest he saves. How much does he save each month?
Answer
Given,
Total salary = ₹ 25440
House rent = 1 4 \dfrac{1}{4} 4 1 part of the salary
Food & clothes = 3 8 \dfrac{3}{8} 8 3 part of the salary
Insurance = 1 10 \dfrac{1}{10} 10 1 part of the salary
Other items = 1 5 \dfrac{1}{5} 5 1 part of the salary
Total fraction spent = 1 4 + 3 8 + 1 10 + 1 5 = 1 × 10 4 × 10 + 3 × 5 8 × 5 + 1 × 4 10 × 4 + 1 × 8 5 × 8 = 10 40 + 15 40 + 4 40 + 8 40 = 10 + 15 + 4 + 8 40 = 37 40 \text{Total fraction spent } = \dfrac{1}{4} + \dfrac{3}{8} + \dfrac{1}{10} + \dfrac{1}{5}\\[1em] = \dfrac{1 \times 10}{4 \times 10} + \dfrac{3 \times 5}{8 \times 5} + \dfrac{1 \times 4}{10 \times 4} + \dfrac{1 \times 8}{5 \times 8}\\[1em] = \dfrac{10}{40} + \dfrac{15}{40} + \dfrac{4}{40} + \dfrac{8}{40}\\[1em] = \dfrac{10 + 15 + 4 + 8}{40}\\[1em] = \dfrac{37}{40}\\[1em] Total fraction spent = 4 1 + 8 3 + 10 1 + 5 1 = 4 × 10 1 × 10 + 8 × 5 3 × 5 + 10 × 4 1 × 4 + 5 × 8 1 × 8 = 40 10 + 40 15 + 40 4 + 40 8 = 40 10 + 15 + 4 + 8 = 40 37
Saving fraction = 1 - Total spent fraction
⇒ Saving fraction = 1 − 37 40 = 40 40 − 37 40 = 40 − 37 40 = 3 40 \Rightarrow \text{Saving fraction } = 1 - \dfrac{37}{40} \\[1em] = \dfrac{40}{40} - \dfrac{37}{40} \\[1em] = \dfrac{40 - 37}{40} \\[1em] = \dfrac{3}{40} \\[1em] ⇒ Saving fraction = 1 − 40 37 = 40 40 − 40 37 = 40 40 − 37 = 40 3
Saving amount = Saving fraction × Salary
= 3 40 × 25 , 440 = 3 × 25 , 440 40 = 76 , 320 40 = 1 , 908 \dfrac{3}{40} \times 25,440 = \dfrac{3 \times 25,440}{40} = \dfrac{76,320}{40} = 1,908 40 3 × 25 , 440 = 40 3 × 25 , 440 = 40 76 , 320 = 1 , 908 .
Hence, saving per month = ₹ 1,908.
An objective test was given to a group of 168 students. It was found that 5 6 \dfrac{5}{6} 6 5 of the students gave all correct answers. How many students made 1 or more mistakes?
Answer
Given,
Total students = 168
Part of students who gave all correct answers = 5 6 \dfrac{5}{6} 6 5
Part of students who made 1 or more mistakes = 1 − 5 6 = 6 − 5 6 = 1 6 1 - \dfrac{5}{6} = \dfrac{6 - 5}{6} = \dfrac{1}{6} 1 − 6 5 = 6 6 − 5 = 6 1 .
Students who made 1 or more mistakes = 1 6 \dfrac{1}{6} 6 1 × Total number of students
= 1 6 × 168 \dfrac{1}{6} \times 168 6 1 × 168
= 28.
Hence, no. of students who made 1 or more mistakes = 28.
In an orchard, 1 3 \dfrac{1}{3} 3 1 of the trees are guava trees, 1 8 \dfrac{1}{8} 8 1 are banana trees and the rest are mango trees. If there are 117 mango trees in the orchard, how many trees in all are there?
Answer
Given,
Part of guava trees = 1 3 \dfrac{1}{3} 3 1
Part of banana trees = 1 8 \dfrac{1}{8} 8 1
Part of mango trees = 1 - (part of guava trees + part of banana trees)
= 1 − ( 1 3 + 1 8 ) = 1 − ( 8 + 3 24 ) = 1 − 11 24 = 24 − 11 24 = 13 24 . = 1 - \Big(\dfrac{1}{3} + \dfrac{1}{8}\Big) \\[1em] = 1 - \Big(\dfrac{8 + 3}{24}\Big) \\[1em] = 1 - \dfrac{11}{24} \\[1em] = \dfrac{24 - 11}{24} \\[1em] = \dfrac{13}{24}. = 1 − ( 3 1 + 8 1 ) = 1 − ( 24 8 + 3 ) = 1 − 24 11 = 24 24 − 11 = 24 13 .
No. of mango trees = Part of mango trees × Total number of trees
117 = 13 24 × Total number of trees Total number of trees = 117 × 24 13 Total number of trees = 9 × 24 = 216. 117 = \dfrac{13}{24} \times \text{Total number of trees} \\[1em] \text{Total number of trees} = 117 \times \dfrac{24}{13} \\[1em] \text{Total number of trees} = 9 \times 24 = 216. 117 = 24 13 × Total number of trees Total number of trees = 117 × 13 24 Total number of trees = 9 × 24 = 216.
Hence, total number of trees = 216.
In a school, 1 25 \dfrac{1}{25} 25 1 of the students were absent on a certain day. If 720 students were present on that day, what is the total number of students in the school?
Answer
Given,
Total students present on a certain day = 720
Part of students absent on a certain day = 1 25 \dfrac{1}{25} 25 1
Part of students present on a certain day = 1 − 1 25 1 - \dfrac{1}{25} 1 − 25 1
= 25 − 1 25 = 24 25 . = \dfrac{25 - 1}{25} \\[1em] = \dfrac{24}{25}. = 25 25 − 1 = 25 24 .
Number of students present on a certain day = Part of students present on a certain day × Total number of students
⇒ 720 = 24 25 × Total number of students ⇒ Total number of students = 720 × 25 24 ⇒ Total number of students = 30 × 25 = 750. \Rightarrow 720 = \dfrac{24}{25} \times \text{ Total number of students} \\[1em] \Rightarrow \text{ Total number of students} = 720 \times \dfrac{25}{24} \\[1em] \Rightarrow \text{ Total number of students} = 30 \times 25 = 750. ⇒ 720 = 25 24 × Total number of students ⇒ Total number of students = 720 × 24 25 ⇒ Total number of students = 30 × 25 = 750.
Hence, total number of students in the school = 750.
The product of three numbers is 7 1 2 7\dfrac{1}{2} 7 2 1 . If two of them are 1 1 7 1\dfrac{1}{7} 1 7 1 and 3 3 4 3\dfrac{3}{4} 3 4 3 , find the third number.
Answer
Given, product of three numbers = 7 1 2 7\dfrac{1}{2} 7 2 1
Two numbers = 1 1 7 1\dfrac{1}{7} 1 7 1 and 3 3 4 3\dfrac{3}{4} 3 4 3
Let the other number be x.
⇒ 1 1 7 × 3 3 4 × x = 7 1 2 ⇒ 8 7 × 15 4 × x = 15 2 ⇒ 8 × 15 7 × 4 × x = 15 2 ⇒ 120 28 × x = 15 2 ⇒ x = 15 × 28 2 × 120 ⇒ x = 420 240 ⇒ x = 7 4 ⇒ x = 1 3 4 . \Rightarrow 1\dfrac{1}{7} \times 3\dfrac{3}{4} \times x = 7\dfrac{1}{2}\\[1em] \Rightarrow \dfrac{8}{7} \times \dfrac{15}{4} \times x = \dfrac{15}{2}\\[1em] \Rightarrow \dfrac{8 \times 15}{7 \times 4} \times x = \dfrac{15}{2}\\[1em] \Rightarrow \dfrac{120}{28} \times x = \dfrac{15}{2}\\[1em] \Rightarrow x = \dfrac{15 \times 28}{2 \times 120}\\[1em] \Rightarrow x = \dfrac{420}{240}\\[1em] \Rightarrow x = \dfrac{7}{4}\\[1em] \Rightarrow x = 1\dfrac{3}{4}. ⇒ 1 7 1 × 3 4 3 × x = 7 2 1 ⇒ 7 8 × 4 15 × x = 2 15 ⇒ 7 × 4 8 × 15 × x = 2 15 ⇒ 28 120 × x = 2 15 ⇒ x = 2 × 120 15 × 28 ⇒ x = 240 420 ⇒ x = 4 7 ⇒ x = 1 4 3 .
Hence, the third number = 1 3 4 1\dfrac{3}{4} 1 4 3 .
Represent each of the following on the number line :
2 3 \dfrac{2}{3} 3 2
Answer
Draw a line. Take a point O in the middle. From O, set off equal distances on right as well as on the left. Mark them, as shown. Now, distance OA = 1 unit.
Divide OA into 3 equal parts. Take 2 parts out of it to reach the point P.
This point P represents 2 3 \dfrac{2}{3} 3 2 on the number line.
Represent each of the following on the number line :
5 8 \dfrac{5}{8} 8 5
Answer
Draw a line. Take a point O in the middle. From O, set off equal distances on right as well as on the left. Mark them, as shown. Now, distance OA = 1 unit.
Divide OA into 8 equal parts. Take 5 parts out of it to reach the point P.
This point P represents 5 8 \dfrac{5}{8} 8 5 on the number line.
Represent each of the following on the number line :
1 2 \dfrac{1}{2} 2 1
Answer
Draw a line. Take a point O in the middle. From O, set off equal distances on right as well as on the left. Mark them, as shown. Now, distance OA = 1 unit.
Divide OA into 2 equal parts. Take 1 part out of it to reach the point P.
This point P represents 1 2 \dfrac{1}{2} 2 1 on the number line.
Represent each of the following on the number line :
3 3 4 3\dfrac{3}{4} 3 4 3
Answer
Let O be the origin. Set off equal distances OA, AB, BC, etc., on right hand side of O, denoting 1, 2, 3, etc.
Take 3 full distances and divide CD into 4 equal parts and take 3 parts out of it to reach the point P.
Hence, the point P represents 3 3 4 3\dfrac{3}{4} 3 4 3 .
Represent each of the following on the number line :
1 4 7 1\dfrac{4}{7} 1 7 4
Answer
Let O be the origin. Set off equal distances OA, AB, BC, etc., on right hand side of O, denoting 1, 2, 3, etc.
Take 1 full distance and divide AB into 7 equal parts. Then, take 4 parts out of it to reach point P.
Hence, the point P represents 1 4 7 1\dfrac{4}{7} 1 7 4 .
Represent each of the following on the number line :
2 2 5 2\dfrac{2}{5} 2 5 2
Answer
Let O be the origin. Set off equal distances OA, AB, BC, etc., on right hand side of O, denoting 1, 2, 3, etc.
Take 2 full distances and divide BC into 5 equal parts and take 2 parts out of it to reach the point P.
Hence, the point P represents 2 2 5 2\dfrac{2}{5} 2 5 2 .
Represent each of the following on the number line :
1 2 + 1 4 \dfrac{1}{2} + \dfrac{1}{4} 2 1 + 4 1
Answer
We know that the L.C.M. of 2 and 4 is 4.
Now, 1 2 = 2 4 \dfrac{1}{2} = \dfrac{2}{4} 2 1 = 4 2 and 1 4 = 1 4 \dfrac{1}{4} = \dfrac{1}{4} 4 1 = 4 1 .
Divide the unit length OA from 0 to 1 into 4 equal parts. Then, each part represents 1 4 \dfrac{1}{4} 4 1 .
From 0 move 2 steps to the the right and then 1 step to the right to reach 3 4 \dfrac{3}{4} 4 3 .
∴ 1 2 + 1 4 = 2 4 + 1 4 = 3 4 \therefore \dfrac{1}{2} + \dfrac{1}{4} = \dfrac{2}{4} + \dfrac{1}{4} = \dfrac{3}{4} ∴ 2 1 + 4 1 = 4 2 + 4 1 = 4 3 , as shown below.
Represent each of the following on the number line :
1 3 + 1 4 \dfrac{1}{3} + \dfrac{1}{4} 3 1 + 4 1
Answer
We know that the L.C.M. of 3 and 4 is 12.
Now, 1 3 = 4 12 \dfrac{1}{3} = \dfrac{4}{12} 3 1 = 12 4 and 1 4 = 3 12 \dfrac{1}{4} = \dfrac{3}{12} 4 1 = 12 3
Divide the unit length OA from 0 to 1 into 12 equal parts. Then, each part represents 1 12 \dfrac{1}{12} 12 1 .
From 0 move 4 steps to the the right and then 3 steps to the right to reach 7 12 \dfrac{7}{12} 12 7 .
∴ 1 3 + 1 4 = 4 12 + 3 12 = 7 12 \therefore \dfrac{1}{3} + \dfrac{1}{4} = \dfrac{4}{12} + \dfrac{3}{12} = \dfrac{7}{12} ∴ 3 1 + 4 1 = 12 4 + 12 3 = 12 7 , as shown below.
Represent each of the following on the number line :
5 6 − 1 6 \dfrac{5}{6} - \dfrac{1}{6} 6 5 − 6 1
Answer
Divide the unit length OA from 0 to 1 into 6 equal parts. Then, each part represents 1 6 \dfrac{1}{6} 6 1 .
From 0 move 5 steps to the the right and then 1 step to the left to reach 4 6 \dfrac{4}{6} 6 4 .
∴ 5 6 − 1 6 = 4 6 \therefore \dfrac{5}{6} - \dfrac{1}{6} = \dfrac{4}{6} ∴ 6 5 − 6 1 = 6 4 , as shown below.
Represent each of the following on the number line :
4 9 − 2 9 \dfrac{4}{9} - \dfrac{2}{9} 9 4 − 9 2
Answer
Divide the unit length OA from 0 to 1 into 9 equal parts. Then, each part represents 1 9 \dfrac{1}{9} 9 1 .
From 0 move 4 steps to the the right and then 2 steps to the left to reach 2 9 \dfrac{2}{9} 9 2 .
∴ 4 9 − 2 9 = 2 9 \therefore \dfrac{4}{9} - \dfrac{2}{9} = \dfrac{2}{9} ∴ 9 4 − 9 2 = 9 2 , as shown below.
Exercise 4(I) — Multiple Choice Questions
48 72 \dfrac{48}{72} 72 48 in simplest form is
8 9 \dfrac{8}{9} 9 8
3 4 \dfrac{3}{4} 4 3
2 3 \dfrac{2}{3} 3 2
none of these
Answer
By prime factorization,
⇒ 48 72 ⇒ 2 × 2 × 2 × 2 × 3 2 × 2 × 2 × 3 × 3 ⇒ 2 3 . \Rightarrow \dfrac{48}{72} \\[1em] \Rightarrow \dfrac{2 \times 2 \times 2 \times 2 \times 3}{2 \times 2 \times 2 \times 3 \times 3} \\[1em] \Rightarrow \dfrac{2}{3}. ⇒ 72 48 ⇒ 2 × 2 × 2 × 3 × 3 2 × 2 × 2 × 2 × 3 ⇒ 3 2 .
Hence, option 3 is the correct option.
42 54 \dfrac{42}{54} 54 42 in simplest form is
3 4 \dfrac{3}{4} 4 3
2 3 \dfrac{2}{3} 3 2
3 7 \dfrac{3}{7} 7 3
7 9 \dfrac{7}{9} 9 7
Answer
By prime factorization,
⇒ 42 54 ⇒ 2 × 3 × 7 2 × 3 × 3 × 3 ⇒ 7 9 . \Rightarrow \dfrac{42}{54} \\[1em] \Rightarrow \dfrac{2 \times 3 \times 7}{2 \times 3 \times 3 \times 3} \\[1em] \Rightarrow \dfrac{7}{9}. ⇒ 54 42 ⇒ 2 × 3 × 3 × 3 2 × 3 × 7 ⇒ 9 7 .
Hence, option 4 is the correct option.
91 114 \dfrac{91}{114} 114 91 in simplest form is
13 8 \dfrac{13}{8} 8 13
7 8 \dfrac{7}{8} 8 7
91 114 \dfrac{91}{114} 114 91
9 13 \dfrac{9}{13} 13 9
Answer
HCF of 91 and 114 = 1.
Thus,
91 114 \dfrac{91}{114} 114 91 in simplest form is 91 114 \dfrac{91}{114} 114 91 .
Hence, option 3 is the correct option.
117 143 \dfrac{117}{143} 143 117 in simplest form is
117 143 \dfrac{117}{143} 143 117
9 11 \dfrac{9}{11} 11 9
13 11 \dfrac{13}{11} 11 13
9 13 \dfrac{9}{13} 13 9
Answer
By prime factorization,
⇒ 117 143 ⇒ 13 × 9 13 × 11 ⇒ 9 11 . \Rightarrow \dfrac{117}{143} \\[1em] \Rightarrow \dfrac{13 \times 9}{13 \times 11} \\[1em] \Rightarrow \dfrac{9}{11}. ⇒ 143 117 ⇒ 13 × 11 13 × 9 ⇒ 11 9 .
Hence, option 2 is the correct option.
If 3 4 \dfrac{3}{4} 4 3 is equivalent to x 20 \dfrac{x}{20} 20 x , then x = ?
12
15
18
16
Answer
Given, 3 4 \dfrac{3}{4} 4 3 is equivalent to x 20 \dfrac{x}{20} 20 x
3 4 = 3 × 5 4 × 5 = 15 20 \dfrac{3}{4} = \dfrac{3 \times 5}{4 \times 5} = \dfrac{15}{20} 4 3 = 4 × 5 3 × 5 = 20 15
Comparing,
x 20 \dfrac{x}{20} 20 x and 15 20 \dfrac{15}{20} 20 15
Thus, x = 15.
Hence, option 2 is the correct option.
If 3 x \dfrac{3}{x} x 3 is equivalent to 45 60 \dfrac{45}{60} 60 45 , then the value of x is
4
5
6
20
Answer
Given, 3 x \dfrac{3}{x} x 3 is equivalent to 45 60 \dfrac{45}{60} 60 45
⇒ 3 x = 45 60 ⇒ x = 3 × 60 45 ⇒ x = 60 15 = 4. \Rightarrow \dfrac{3}{x} = \dfrac{45}{60} \\[1em] \Rightarrow x = \dfrac{3 \times 60}{45} \\[1em] \Rightarrow x = \dfrac{60}{15} = 4. ⇒ x 3 = 60 45 ⇒ x = 45 3 × 60 ⇒ x = 15 60 = 4.
Hence, option 1 is the correct option.
Which of the following are the like fractions?
2 3 , 2 5 , 2 7 , 2 9 \dfrac{2}{3}, \dfrac{2}{5}, \dfrac{2}{7}, \dfrac{2}{9} 3 2 , 5 2 , 7 2 , 9 2
2 3 , 3 4 , 4 5 , 5 6 \dfrac{2}{3}, \dfrac{3}{4}, \dfrac{4}{5}, \dfrac{5}{6} 3 2 , 4 3 , 5 4 , 6 5
1 5 , 2 5 , 3 5 , 4 5 \dfrac{1}{5}, \dfrac{2}{5}, \dfrac{3}{5}, \dfrac{4}{5} 5 1 , 5 2 , 5 3 , 5 4
none of these
Answer
Like fractions are fractions that have the same denominator.
In option 3,
1 5 , 2 5 , 3 5 , 4 5 \dfrac{1}{5}, \dfrac{2}{5}, \dfrac{3}{5}, \dfrac{4}{5} 5 1 , 5 2 , 5 3 , 5 4
Denominators = 5, 5, 5 and 5
All denominators are same.
So, they are like fractions.
Hence, option 3 is the correct option.
Which of the following is an improper fraction?
5 7 \dfrac{5}{7} 7 5
4 7 \dfrac{4}{7} 7 4
7 7 \dfrac{7}{7} 7 7
2 3 \dfrac{2}{3} 3 2
Answer
An improper fraction is a fraction in which the numerator is greater than or equal to the denominator.
In option 3, 7 7 \dfrac{7}{7} 7 7 ; numerator = denominator = 7
Hence, option 3 is the correct option.
Which of the following is a proper fraction ?
5 5 \dfrac{5}{5} 5 5
6 5 \dfrac{6}{5} 5 6
4 3 \dfrac{4}{3} 3 4
3 4 \dfrac{3}{4} 4 3
Answer
A proper fraction is a fraction in which the numerator is less than the denominator.
In option 4, 3 4 \dfrac{3}{4} 4 3 ; numerator < denominator
Hence, option 4 is the correct option.
Which of the following statements is correct ?
2 3 > 3 5 \dfrac{2}{3} \gt \dfrac{3}{5} 3 2 > 5 3
2 3 < 3 5 \dfrac{2}{3} \lt \dfrac{3}{5} 3 2 < 5 3
2 3 = 3 5 \dfrac{2}{3} = \dfrac{3}{5} 3 2 = 5 3
2 3 \dfrac{2}{3} 3 2 and 3 5 \dfrac{3}{5} 5 3 cannot be compared
Answer
Comparing both fractions; 2 3 \dfrac{2}{3} 3 2 and 3 5 \dfrac{3}{5} 5 3
Cross multiply: 2 x 5 and 3 x 3
⇒ 10 and 9
Now, comparing both numbers;
⇒ 10 > 9
⇒ 2 3 > 3 5 \dfrac{2}{3} \gt \dfrac{3}{5} 3 2 > 5 3
Hence, option 1 is the correct option.
The smallest of the fractions 3 5 , 5 6 , 7 10 , 2 3 \dfrac{3}{5}, \dfrac{5}{6}, \dfrac{7}{10}, \dfrac{2}{3} 5 3 , 6 5 , 10 7 , 3 2 is
2 3 \dfrac{2}{3} 3 2
3 5 \dfrac{3}{5} 5 3
5 6 \dfrac{5}{6} 6 5
7 10 \dfrac{7}{10} 10 7
Answer
Given fractions: 3 5 , 5 6 , 7 10 , 2 3 \dfrac{3}{5}, \dfrac{5}{6}, \dfrac{7}{10}, \dfrac{2}{3} 5 3 , 6 5 , 10 7 , 3 2
LCM of the denominators (5, 6, 10, 3) = 30
⇒ 3 × 6 5 × 6 , 5 × 5 6 × 5 , 7 × 3 10 × 3 , 2 × 10 3 × 10 ⇒ 18 30 , 25 30 , 21 30 , 20 30 \Rightarrow \dfrac{3 \times 6}{5 \times 6}, \dfrac{5 \times 5}{6 \times 5}, \dfrac{7 \times 3}{10 \times 3}, \dfrac{2 \times 10}{3 \times 10}\\[1em] \Rightarrow \dfrac{18}{30}, \dfrac{25}{30}, \dfrac{21}{30}, \dfrac{20}{30} ⇒ 5 × 6 3 × 6 , 6 × 5 5 × 5 , 10 × 3 7 × 3 , 3 × 10 2 × 10 ⇒ 30 18 , 30 25 , 30 21 , 30 20
Among fractions with the same denominator, the one with the smaller numerator is smaller.
So, 18 30 < 20 30 < 21 30 < 25 30 \dfrac{18}{30} \lt \dfrac{20}{30} \lt \dfrac{21}{30} \lt \dfrac{25}{30} 30 18 < 30 20 < 30 21 < 30 25
3 5 < 2 3 < 7 10 < 5 6 \dfrac{3}{5} \lt \dfrac{2}{3} \lt \dfrac{7}{10} \lt \dfrac{5}{6} 5 3 < 3 2 < 10 7 < 6 5
Hence, option 2 is the correct option.
The largest of the fractions 5 6 , 5 7 , 5 9 , 5 11 \dfrac{5}{6}, \dfrac{5}{7}, \dfrac{5}{9}, \dfrac{5}{11} 6 5 , 7 5 , 9 5 , 11 5 is
5 11 \dfrac{5}{11} 11 5
5 9 \dfrac{5}{9} 9 5
5 7 \dfrac{5}{7} 7 5
5 6 \dfrac{5}{6} 6 5
Answer
Given fractions: 5 6 , 5 7 , 5 9 , 5 11 \dfrac{5}{6}, \dfrac{5}{7}, \dfrac{5}{9}, \dfrac{5}{11} 6 5 , 7 5 , 9 5 , 11 5
LCM of the denominators (6, 7, 9, 11) = 1,386
⇒ 5 × 231 6 × 231 , 5 × 198 7 × 198 , 5 × 154 9 × 154 , 5 × 126 11 × 126 ⇒ 1155 1386 , 990 1386 , 770 1386 , 630 1386 \Rightarrow \dfrac{5 \times 231}{6 \times 231}, \dfrac{5 \times 198}{7 \times 198}, \dfrac{5 \times 154}{9 \times 154}, \dfrac{5 \times 126}{11 \times 126}\\[1em] \Rightarrow \dfrac{1155}{1386}, \dfrac{990}{1386}, \dfrac{770}{1386}, \dfrac{630}{1386} ⇒ 6 × 231 5 × 231 , 7 × 198 5 × 198 , 9 × 154 5 × 154 , 11 × 126 5 × 126 ⇒ 1386 1155 , 1386 990 , 1386 770 , 1386 630
Among fractions with the same denominator, the one with the smaller numerator is smaller.
So, 630 1386 < 770 1386 < 990 1386 < 1155 1386 \dfrac{630}{1386} \lt \dfrac{770}{1386} \lt \dfrac{990}{1386} \lt \dfrac{1155}{1386} 1386 630 < 1386 770 < 1386 990 < 1386 1155
5 11 < 5 9 < 5 7 < 5 6 \dfrac{5}{11} \lt \dfrac{5}{9} \lt \dfrac{5}{7} \lt \dfrac{5}{6} 11 5 < 9 5 < 7 5 < 6 5
Hence, option 4 is the correct option.
The smallest of the fractions 8 13 , 9 13 , 10 13 , 11 13 \dfrac{8}{13}, \dfrac{9}{13}, \dfrac{10}{13}, \dfrac{11}{13} 13 8 , 13 9 , 13 10 , 13 11 is
11 13 \dfrac{11}{13} 13 11
10 13 \dfrac{10}{13} 13 10
8 13 \dfrac{8}{13} 13 8
9 13 \dfrac{9}{13} 13 9
Answer
Given fractions: 8 13 , 9 13 , 10 13 , 11 13 \dfrac{8}{13}, \dfrac{9}{13}, \dfrac{10}{13}, \dfrac{11}{13} 13 8 , 13 9 , 13 10 , 13 11
Among fractions with same denominator, the one with greater numerator is greater of the two.
So, 8 13 < 9 13 < 10 13 < 11 13 \dfrac{8}{13} \lt \dfrac{9}{13} \lt \dfrac{10}{13} \lt \dfrac{11}{13} 13 8 < 13 9 < 13 10 < 13 11
Hence, option 3 is the correct option.
The smallest of the fractions 3 4 , 5 6 , 7 12 , 2 3 \dfrac{3}{4}, \dfrac{5}{6}, \dfrac{7}{12}, \dfrac{2}{3} 4 3 , 6 5 , 12 7 , 3 2 is
2 3 \dfrac{2}{3} 3 2
3 4 \dfrac{3}{4} 4 3
5 6 \dfrac{5}{6} 6 5
7 12 \dfrac{7}{12} 12 7
Answer
Given fractions: 3 4 , 5 6 , 7 12 , 2 3 \dfrac{3}{4}, \dfrac{5}{6}, \dfrac{7}{12}, \dfrac{2}{3} 4 3 , 6 5 , 12 7 , 3 2
LCM of the denominators (4, 6, 12, 3) = 12
⇒ 3 × 3 4 × 3 , 5 × 2 6 × 2 , 7 × 1 12 × 1 , 2 × 4 3 × 4 ⇒ 9 12 , 10 12 , 7 12 , 8 12 \Rightarrow \dfrac{3 \times 3}{4 \times 3}, \dfrac{5 \times 2}{6 \times 2}, \dfrac{7 \times 1}{12 \times 1}, \dfrac{2 \times 4}{3 \times 4}\\[1em] \Rightarrow \dfrac{9}{12}, \dfrac{10}{12}, \dfrac{7}{12}, \dfrac{8}{12} ⇒ 4 × 3 3 × 3 , 6 × 2 5 × 2 , 12 × 1 7 × 1 , 3 × 4 2 × 4 ⇒ 12 9 , 12 10 , 12 7 , 12 8
Among two fractions with same denominator, the one with greater numerator is greater of the two.
So, 7 12 < 8 12 < 9 12 < 10 12 \dfrac{7}{12} \lt \dfrac{8}{12} \lt \dfrac{9}{12} \lt \dfrac{10}{12} 12 7 < 12 8 < 12 9 < 12 10
7 12 < 2 3 < 3 4 < 5 6 \dfrac{7}{12} \lt \dfrac{2}{3} \lt \dfrac{3}{4} \lt \dfrac{5}{6} 12 7 < 3 2 < 4 3 < 6 5
Hence, option 4 is the correct option.
37 5 = ? \dfrac{37}{5} = ? 5 37 = ?
7 1 5 7\dfrac{1}{5} 7 5 1
7 2 5 7\dfrac{2}{5} 7 5 2
7 3 5 7\dfrac{3}{5} 7 5 3
7 4 5 7\dfrac{4}{5} 7 5 4
Answer
Given; 37 5 \dfrac{37}{5} 5 37
Divide 37 by 5: 37 ÷ 5 = 7 with a remainder of 2.
The quotient is 7 and the remainder 2 becomes the numerator.
37 5 = 7 2 5 \dfrac{37}{5} = 7\dfrac{2}{5} 5 37 = 7 5 2
Hence, option 2 is the correct option.
The reciprocal of 1 5 7 1\dfrac{5}{7} 1 7 5 is
12 7 \dfrac{12}{7} 7 12
1 7 5 1\dfrac{7}{5} 1 5 7
7 12 \dfrac{7}{12} 12 7
none of these
Answer
1 5 7 = 7 × 1 + 5 7 = 12 7 1\dfrac{5}{7} = \dfrac{7 \times 1 + 5}{7} = \dfrac{12}{7} 1 7 5 = 7 7 × 1 + 5 = 7 12 .
The reciprocal of 12 7 \dfrac{12}{7} 7 12 is 7 12 \dfrac{7}{12} 12 7 .
Hence, option 3 is the correct option.
1 ÷ 5 7 = ? \dfrac{5}{7} = ? 7 5 = ?
2 5 \dfrac{2}{5} 5 2
5 2 \dfrac{5}{2} 2 5
7 2 \dfrac{7}{2} 2 7
none of these
Answer
Given,
⇒ 1 ÷ 5 7 ⇒ 1 × 7 5 ⇒ 1 × 7 5 ⇒ 7 5 . \Rightarrow 1 ÷ \dfrac{5}{7}\\[1em] \Rightarrow 1 \times \dfrac{7}{5}\\[1em] \Rightarrow \dfrac{1 \times 7}{5}\\[1em] \Rightarrow \dfrac{7}{5}. ⇒ 1 ÷ 7 5 ⇒ 1 × 5 7 ⇒ 5 1 × 7 ⇒ 5 7 .
Hence, option 4 is the correct option.
4 5 \dfrac{4}{5} 5 4 of a number is 64. Half of that number is
32
40
80
16
Answer
Given, 4 5 \dfrac{4}{5} 5 4 of a number is 64.
Let the number be x.
⇒ 4 5 × x = 64 ⇒ x = 64 ÷ 4 5 ⇒ x = 64 × 5 4 ⇒ x = 64 × 5 4 ⇒ x = 16 × 5 ⇒ x = 80. \Rightarrow \dfrac{4}{5} \times x = 64\\[1em] \Rightarrow x = 64 ÷ \dfrac{4}{5} \\[1em] \Rightarrow x = 64 \times \dfrac{5}{4} \\[1em] \Rightarrow x = \dfrac{64 \times 5}{4} \\[1em] \Rightarrow x = 16 \times 5 \\[1em] \Rightarrow x = 80. ⇒ 5 4 × x = 64 ⇒ x = 64 ÷ 5 4 ⇒ x = 64 × 4 5 ⇒ x = 4 64 × 5 ⇒ x = 16 × 5 ⇒ x = 80.
Half of the number = 1 2 × 80 = 80 2 = 40 \dfrac{1}{2} \times 80 = \dfrac{80}{2} = 40 2 1 × 80 = 2 80 = 40 .
Hence, option 2 is the correct option.
Exercise 4(I) — Mental Maths
Fill in the blanks :
(i) 7 11 \dfrac{7}{11} 11 7 ............... 5 8 \dfrac{5}{8} 8 5
(ii) 3 7 \dfrac{3}{7} 7 3 ............... 3 5 \dfrac{3}{5} 5 3
(iii) 4 9 \dfrac{4}{9} 9 4 ............... 4 7 \dfrac{4}{7} 7 4
(iv) 15 4 × \dfrac{15}{4} \times 4 15 × ............... = 3 2 \dfrac{3}{2} 2 3
(v) 14 15 \dfrac{14}{15} 15 14 ÷ ............... = 2 3 \dfrac{2}{3} 3 2
(vi) Reciprocal of 2 3 4 2\dfrac{3}{4} 2 4 3 is ...............
Answer
(i) 7 11 \dfrac{7}{11} 11 7 ............... 5 8 \dfrac{5}{8} 8 5
Cross multiply; 7 x 8 and 5 x 11
⇒ 56 and 55
Now, comparing both numbers;
⇒ 56 > 55
Hence, 7 11 \dfrac{7}{11} 11 7 > {\boxed{\gt}} > 5 8 \dfrac{5}{8} 8 5
(ii) 3 7 \dfrac{3}{7} 7 3 ............... 3 5 \dfrac{3}{5} 5 3
Cross multiply; 3 x 5 and 3 x 7
⇒ 15 and 35
Now, comparing both numbers;
⇒ 15 < 35
Hence, 3 7 \dfrac{3}{7} 7 3 < {\boxed{\lt}} < 3 5 \dfrac{3}{5} 5 3
(iii) 4 9 \dfrac{4}{9} 9 4 ............... 4 7 \dfrac{4}{7} 7 4
Cross multiply; 4 x 7 and 4 x 9
⇒ 28 and 36
Now, comparing both numbers;
⇒ 28 < 36
Hence, 4 9 \dfrac{4}{9} 9 4 < {\boxed{\lt}} < 4 7 \dfrac{4}{7} 7 4
(iv) 15 4 × \dfrac{15}{4} \times 4 15 × ............... = 3 2 \dfrac{3}{2} 2 3
Let 15 4 × x = 3 2 \dfrac{15}{4} \times x = \dfrac{3}{2} 4 15 × x = 2 3
Solving,
⇒ x = 3 2 ÷ 15 4 ⇒ x = 3 2 × 4 15 ⇒ x = 3 × 4 2 × 15 ⇒ x = 12 30 ⇒ x = 2 5 \Rightarrow x = \dfrac{3}{2} ÷ \dfrac{15}{4}\\[1em] \Rightarrow x = \dfrac{3}{2} \times \dfrac{4}{15}\\[1em] \Rightarrow x = \dfrac{3 \times 4}{2 \times 15}\\[1em] \Rightarrow x = \dfrac{12}{30}\\[1em] \Rightarrow x = \dfrac{2}{5} ⇒ x = 2 3 ÷ 4 15 ⇒ x = 2 3 × 15 4 ⇒ x = 2 × 15 3 × 4 ⇒ x = 30 12 ⇒ x = 5 2
Hence, 15 4 × 2 5 = 3 2 \dfrac{15}{4} \times \dfrac{2}{5} = \dfrac{3}{2} 4 15 × 5 2 = 2 3
(v) 14 15 \dfrac{14}{15} 15 14 ÷ ............... = 2 3 \dfrac{2}{3} 3 2
Let 14 15 ÷ x = 2 3 \dfrac{14}{15} \div x = \dfrac{2}{3} 15 14 ÷ x = 3 2
Solving,
⇒ 14 15 ÷ x = 2 3 ⇒ x = 14 15 ÷ 2 3 ⇒ x = 14 15 × 3 2 ⇒ x = 14 × 3 15 × 2 ⇒ x = 42 30 ⇒ x = 7 5 . \Rightarrow \dfrac{14}{15} ÷ x = \dfrac{2}{3}\\[1em] \Rightarrow x = \dfrac{14}{15} ÷ \dfrac{2}{3} \\[1em] \Rightarrow x = \dfrac{14}{15} \times \dfrac{3}{2} \\[1em] \Rightarrow x = \dfrac{14 \times 3}{15 \times 2}\\[1em] \Rightarrow x = \dfrac{42}{30}\\[1em] \Rightarrow x = \dfrac{7}{5}. ⇒ 15 14 ÷ x = 3 2 ⇒ x = 15 14 ÷ 3 2 ⇒ x = 15 14 × 2 3 ⇒ x = 15 × 2 14 × 3 ⇒ x = 30 42 ⇒ x = 5 7 .
Hence, 14 15 ÷ 7 5 = 2 3 \dfrac{14}{15} ÷ \dfrac{7}{5} = \dfrac{2}{3} 15 14 ÷ 5 7 = 3 2
(vi) Reciprocal of 2 3 4 2\dfrac{3}{4} 2 4 3 is ...............
Reciprocal of 2 3 4 = 11 4 2\dfrac{3}{4} = \dfrac{11}{4} 2 4 3 = 4 11 is 4 11 \dfrac{4}{11} 11 4
Hence, reciprocal of 2 3 4 2\dfrac{3}{4} 2 4 3 is 4 11 \dfrac{4}{11} 11 4 .
Fill in the blanks :
(i) 8 5 \dfrac{8}{5} 5 8 ÷ 1 = ...............
(ii) 1 3 8 1\dfrac{3}{8} 1 8 3 of 4 5 \dfrac{4}{5} 5 4 = ...............
(iii) ( 5 6 of 1 hour ) \Big(\dfrac{5}{6} \text{ of 1 hour}\Big) ( 6 5 of 1 hour ) = ............... minutes
(iv) ( 3 8 of 1 km ) \Big(\dfrac{3}{8} \text{ of 1 km}\Big) ( 8 3 of 1 km ) = ............... metre
(v) ( 3 5 of ₹ 1 ) \Big(\dfrac{3}{5} \text{ of ₹ 1}\Big) ( 5 3 of ₹ 1 ) = ............... paise
Answer
(i) 8 5 \dfrac{8}{5} 5 8 ÷ 1 = ...............
⇒ 8 5 ÷ 1 ⇒ 8 5 × 1 1 ⇒ 8 × 1 5 × 1 ⇒ 8 5 ⇒ 1 3 5 \Rightarrow \dfrac{8}{5} ÷ 1\\[1em] \Rightarrow \dfrac{8}{5} \times \dfrac{1}{1}\\[1em] \Rightarrow \dfrac{8 \times 1}{5 \times 1}\\[1em] \Rightarrow \dfrac{8}{5}\\[1em] \Rightarrow 1\dfrac{3}{5} ⇒ 5 8 ÷ 1 ⇒ 5 8 × 1 1 ⇒ 5 × 1 8 × 1 ⇒ 5 8 ⇒ 1 5 3
Hence, 8 5 ÷ 1 = 1 3 5 \dfrac{8}{5} ÷ 1 = 1\dfrac{3}{5} 5 8 ÷ 1 = 1 5 3 .
(ii) 1 3 8 1\dfrac{3}{8} 1 8 3 of 4 5 \dfrac{4}{5} 5 4 ...............
⇒ 1 3 8 × 4 5 ⇒ 11 8 × 4 5 ⇒ 11 × 4 8 × 5 ⇒ 44 40 ⇒ 11 10 ⇒ 1 1 10 \Rightarrow 1\dfrac{3}{8} \times \dfrac{4}{5}\\[1em] \Rightarrow \dfrac{11}{8} \times \dfrac{4}{5}\\[1em] \Rightarrow \dfrac{11 \times 4}{8 \times 5}\\[1em] \Rightarrow \dfrac{44}{40}\\[1em] \Rightarrow \dfrac{11}{10}\\[1em] \Rightarrow 1\dfrac{1}{10}\\[1em] ⇒ 1 8 3 × 5 4 ⇒ 8 11 × 5 4 ⇒ 8 × 5 11 × 4 ⇒ 40 44 ⇒ 10 11 ⇒ 1 10 1
Hence, 1 3 8 1\dfrac{3}{8} 1 8 3 of 4 5 = 11 10 \dfrac{4}{5} = \dfrac{11}{10} 5 4 = 10 11 .
(iii) ( 5 6 of 1 hour ) \Big(\dfrac{5}{6} \text{ of 1 hour}\Big) ( 6 5 of 1 hour ) = ............... minutes
⇒ 5 6 of 1 hour ⇒ 5 6 of 60 minutes ⇒ 5 6 × 60 ⇒ 5 × 60 6 ⇒ 300 6 ⇒ 50 \Rightarrow \dfrac{5}{6} \text{ of 1 hour}\\[1em] \Rightarrow \dfrac{5}{6} \text{ of 60 minutes}\\[1em] \Rightarrow \dfrac{5}{6} \times 60 \\[1em] \Rightarrow \dfrac{5 \times 60}{6} \\[1em] \Rightarrow \dfrac{300}{6} \\[1em] \Rightarrow 50 ⇒ 6 5 of 1 hour ⇒ 6 5 of 60 minutes ⇒ 6 5 × 60 ⇒ 6 5 × 60 ⇒ 6 300 ⇒ 50
Hence, ( 5 6 of 1 hour ) \Big(\dfrac{5}{6} \text{ of 1 hour}\Big) ( 6 5 of 1 hour ) = 50 minutes.
(iv) ( 3 8 of 1 km ) \Big(\dfrac{3}{8} \text{ of 1 km}\Big) ( 8 3 of 1 km ) = ............... metre
⇒ 3 8 of 1 km ⇒ 3 8 of 1,000 m ⇒ 3 8 × 1 , 000 ⇒ 3 × 1 , 000 8 ⇒ 3 , 000 8 ⇒ 375 \Rightarrow \dfrac{3}{8} \text{ of 1 km}\\[1em] \Rightarrow \dfrac{3}{8} \text{ of 1,000 m}\\[1em] \Rightarrow \dfrac{3}{8} \times 1,000\\[1em] \Rightarrow \dfrac{3 \times 1,000}{8}\\[1em] \Rightarrow \dfrac{3,000}{8}\\[1em] \Rightarrow 375 ⇒ 8 3 of 1 km ⇒ 8 3 of 1,000 m ⇒ 8 3 × 1 , 000 ⇒ 8 3 × 1 , 000 ⇒ 8 3 , 000 ⇒ 375
Hence, ( 3 8 of 1 km ) \Big(\dfrac{3}{8} \text{ of 1 km}\Big) ( 8 3 of 1 km ) = 375 metres.
(v) ( 3 5 of ₹ 1 ) \Big(\dfrac{3}{5} \text{ of ₹ 1}\Big) ( 5 3 of ₹ 1 ) = ............... paise
⇒ ( 3 5 of ₹ 1 ) ⇒ ( 3 5 of 100 paise ) ⇒ 3 5 × 100 ⇒ 3 × 100 5 ⇒ 300 5 ⇒ 60 \Rightarrow \Big(\dfrac{3}{5} \text{ of ₹ 1}\Big)\\[1em] \Rightarrow \Big(\dfrac{3}{5} \text{ of 100 paise}\Big)\\[1em] \Rightarrow \dfrac{3}{5} \times 100 \\[1em] \Rightarrow \dfrac{3 \times 100}{5}\\[1em] \Rightarrow \dfrac{300}{5}\\[1em] \Rightarrow 60 ⇒ ( 5 3 of ₹ 1 ) ⇒ ( 5 3 of 100 paise ) ⇒ 5 3 × 100 ⇒ 5 3 × 100 ⇒ 5 300 ⇒ 60
Hence, ( 3 5 of ₹ 1 ) \Big(\dfrac{3}{5} \text{ of ₹ 1}\Big) ( 5 3 of ₹ 1 ) = 60 paise.
Write T for true and F for false statement :
1 ÷ 3 2 \dfrac{3}{2} 2 3 = 2 3 \dfrac{2}{3} 3 2 .
Answer
True
Reason
Given, 1 ÷ 3 2 \dfrac{3}{2} 2 3 = 2 3 \dfrac{2}{3} 3 2 .
Taking L.H.S.
⇒ 1 ÷ 3 2 ⇒ 1 × 2 3 ⇒ 1 × 2 3 ⇒ 2 3 \Rightarrow 1 ÷ \dfrac{3}{2}\\[1em] \Rightarrow 1 \times \dfrac{2}{3}\\[1em] \Rightarrow \dfrac{1 \times 2}{3}\\[1em] \Rightarrow \dfrac{2}{3} ⇒ 1 ÷ 2 3 ⇒ 1 × 3 2 ⇒ 3 1 × 2 ⇒ 3 2
Taking R.H.S. = 2 3 \dfrac{2}{3} 3 2 .
Since, L.H.S. = R.H.S.
Write T for true and F for false statement :
1 2 3 1\dfrac{2}{3} 1 3 2 ÷ 3 4 \dfrac{3}{4} 4 3 = 1 1 2 1\dfrac{1}{2} 1 2 1 .
Answer
False
Reason
Given, 1 2 3 1\dfrac{2}{3} 1 3 2 ÷ 3 4 \dfrac{3}{4} 4 3 = 1 1 2 1\dfrac{1}{2} 1 2 1 .
Taking L.H.S.
⇒ 1 2 3 ÷ 3 4 ⇒ 5 3 ÷ 3 4 ⇒ 5 3 × 4 3 ⇒ 5 × 4 3 × 3 ⇒ 20 9 ⇒ 2 2 9 \Rightarrow 1\dfrac{2}{3} ÷ \dfrac{3}{4}\\[1em] \Rightarrow \dfrac{5}{3} ÷ \dfrac{3}{4}\\[1em] \Rightarrow \dfrac{5}{3} \times \dfrac{4}{3}\\[1em] \Rightarrow \dfrac{5 \times 4}{3 \times 3}\\[1em] \Rightarrow \dfrac{20}{9}\\[1em] \Rightarrow 2\dfrac{2}{9}\\[1em] ⇒ 1 3 2 ÷ 4 3 ⇒ 3 5 ÷ 4 3 ⇒ 3 5 × 3 4 ⇒ 3 × 3 5 × 4 ⇒ 9 20 ⇒ 2 9 2
Taking R.H.S. = 1 1 2 1\dfrac{1}{2} 1 2 1
Since, L.H.S. ≠ R.H.S.
Write T for true and F for false statement :
3 5 \dfrac{3}{5} 5 3 of 1 kg = 600 g.
Answer
True
Reason
Given, 3 5 \dfrac{3}{5} 5 3 of 1 kg = 600 g.
Taking L.H.S.
⇒ 3 5 of 1 kg ⇒ 3 5 of 1000 g ⇒ 3 5 × 1000 ⇒ 3 × 1000 5 ⇒ 3000 5 ⇒ 600 \Rightarrow \dfrac{3}{5} \text{ of 1 kg}\\[1em] \Rightarrow \dfrac{3}{5} \text{ of 1000 g}\\[1em] \Rightarrow \dfrac{3}{5} \times 1000\\[1em] \Rightarrow \dfrac{3 \times 1000}{5}\\[1em] \Rightarrow \dfrac{3000}{5}\\[1em] \Rightarrow 600 ⇒ 5 3 of 1 kg ⇒ 5 3 of 1000 g ⇒ 5 3 × 1000 ⇒ 5 3 × 1000 ⇒ 5 3000 ⇒ 600
Taking R.H.S. = 600 g
Since, L.H.S. = R.H.S.
Write T for true and F for false statement :
3 4 \dfrac{3}{4} 4 3 of ₹ 1 = 65 paise.
Answer
False
Reason
Given, 3 4 \dfrac{3}{4} 4 3 of ₹ 1 = 65 paise.
Taking L.H.S.
⇒ 3 4 of ₹ 1 ⇒ 3 4 of 100 paise ⇒ 3 × 100 4 ⇒ 300 4 ⇒ 75 \Rightarrow \dfrac{3}{4} \text{ of ₹ 1}\\[1em] \Rightarrow \dfrac{3}{4} \text{ of 100 paise}\\[1em] \Rightarrow \dfrac{3 \times 100}{4} \\[1em] \Rightarrow \dfrac{300}{4} \\[1em] \Rightarrow 75 ⇒ 4 3 of ₹ 1 ⇒ 4 3 of 100 paise ⇒ 4 3 × 100 ⇒ 4 300 ⇒ 75
Taking R.H.S. = 65 paise
Since, L.H.S. ≠ R.H.S.
Write T for true and F for false statement :
7 10 \dfrac{7}{10} 10 7 of 1 hour = 42 minutes.
Answer
True
Reason
Given, 7 10 \dfrac{7}{10} 10 7 of 1 hour = 42 minutes.
Taking L.H.S.
⇒ 7 10 of 1 hour ⇒ 7 10 of 60 minutes ⇒ 7 10 × 60 ⇒ 7 × 60 10 ⇒ 420 10 ⇒ 42 \Rightarrow \dfrac{7}{10} \text{ of 1 hour}\\[1em] \Rightarrow \dfrac{7}{10} \text{ of 60 minutes}\\[1em] \Rightarrow \dfrac{7}{10} \times 60 \\[1em] \Rightarrow \dfrac{7 \times 60}{10}\\[1em] \Rightarrow \dfrac{420}{10}\\[1em] \Rightarrow 42 ⇒ 10 7 of 1 hour ⇒ 10 7 of 60 minutes ⇒ 10 7 × 60 ⇒ 10 7 × 60 ⇒ 10 420 ⇒ 42
Taking R.H.S. = 42 minutes
Since, L.H.S. = R.H.S.
Write T for true and F for false statement :
5 6 \dfrac{5}{6} 6 5 and 5 7 \dfrac{5}{7} 7 5 are like fractions.
Answer
False
Reason
Given, 5 6 \dfrac{5}{6} 6 5 and 5 7 \dfrac{5}{7} 7 5
Since denominator of both fractions are different. So, these are unlike fractions.
Write T for true and F for false statement :
1 4 \dfrac{1}{4} 4 1 and 1 5 \dfrac{1}{5} 5 1 are unlike fractions.
Answer
True
Reason
Given, 1 4 \dfrac{1}{4} 4 1 and 1 5 \dfrac{1}{5} 5 1
Since denominator of both fractions are different. So, these are unlike fraction.
Exercise 4(I) — Case Study Based Questions
A man spends 2 5 \dfrac{2}{5} 5 2 of his salary on house-rent, 3 10 \dfrac{3}{10} 10 3 of his salary on food and 1 8 \dfrac{1}{8} 8 1 of his salary on conveyance. He saves the remaining ₹ 10,500.
The total salary of the man is : (a) ₹ 52,500 (b) ₹ 55,000 (c) ₹ 57,500 (d) ₹ 60,000
The amount spent on house-rent is : (a) ₹ 30,000 (b) ₹ 26,000 (c) ₹ 24,000 (d) ₹ 28,000
The amount spent on food is : (a) ₹ 18,000 (b) ₹ 20,000 (c) ₹ 22,500 (d) ₹ 24,000
The amount spent on conveyance is : (a) ₹ 12,000 (b) ₹ 10,500 (c) ₹ 7,500 (d) ₹ 15,000
Answer
1. Given,
Part spent on house-rent = 2 5 \dfrac{2}{5} 5 2
Part spent on food = 3 10 \dfrac{3}{10} 10 3
Part spent on conveyance = 1 8 \dfrac{1}{8} 8 1
Savings = ₹ 10,500.
⇒ Total fraction spent = 2 5 + 3 10 + 1 8 ⇒ 2 × 8 5 × 8 + 3 × 4 10 × 4 + 1 × 5 8 × 5 ⇒ 16 40 + 12 40 + 5 40 ⇒ 16 + 12 + 5 40 ⇒ 33 40 \Rightarrow \text{Total fraction spent } = \dfrac{2}{5} + \dfrac{3}{10} + \dfrac{1}{8}\\[1em] \Rightarrow \dfrac{2 \times 8}{5 \times 8} + \dfrac{3 \times 4}{10 \times 4} + \dfrac{1 \times 5}{8 \times 5}\\[1em] \Rightarrow \dfrac{16}{40} + \dfrac{12}{40} + \dfrac{5}{40}\\[1em] \Rightarrow \dfrac{16 + 12 + 5}{40}\\[1em] \Rightarrow \dfrac{33}{40}\\[1em] ⇒ Total fraction spent = 5 2 + 10 3 + 8 1 ⇒ 5 × 8 2 × 8 + 10 × 4 3 × 4 + 8 × 5 1 × 5 ⇒ 40 16 + 40 12 + 40 5 ⇒ 40 16 + 12 + 5 ⇒ 40 33
Savings fraction = 1 − 33 40 = 40 − 33 40 = 7 40 1 - \dfrac{33}{40} = \dfrac{40 - 33}{40} = \dfrac{7}{40} 1 − 40 33 = 40 40 − 33 = 40 7 .
Savings = Savings fraction × Total salary
⇒ 10500 = 7 40 × Total salary ⇒ Total salary = 10500 × 40 7 ⇒ Total salary = 1500 × 40 = ₹ 60 , 000. \Rightarrow 10500 = \dfrac{7}{40} \times \text{Total salary} \\[1em] \Rightarrow \text{Total salary} = \dfrac{10500 \times 40}{7} \\[1em] \Rightarrow \text{Total salary} = 1500 \times 40 = ₹60,000. ⇒ 10500 = 40 7 × Total salary ⇒ Total salary = 7 10500 × 40 ⇒ Total salary = 1500 × 40 = ₹60 , 000.
Hence, option (d) is the correct option.
2. Amount spent on house rent = 2 5 \dfrac{2}{5} 5 2 of the salary
= 2 5 × 60 , 000 = 2 × 60 , 000 5 = 1 , 20 , 000 5 = ₹ 24 , 000. = \dfrac{2}{5} \times 60,000 \\[1em] = \dfrac{2 \times 60,000}{5}\\[1em] = \dfrac{1,20,000}{5}\\[1em] = ₹24,000. = 5 2 × 60 , 000 = 5 2 × 60 , 000 = 5 1 , 20 , 000 = ₹24 , 000.
Hence, option (c) is the correct option.
3. Amount spent on food = 3 10 \dfrac{3}{10} 10 3 of the salary
= 3 10 × 60 , 000 = 3 × 60 , 000 10 = 1 , 80 , 000 10 = ₹ 18 , 000 = \dfrac{3}{10} \times 60,000 \\[1em] = \dfrac{3 \times 60,000}{10}\\[1em] = \dfrac{1,80,000}{10}\\[1em] = ₹18,000 = 10 3 × 60 , 000 = 10 3 × 60 , 000 = 10 1 , 80 , 000 = ₹18 , 000
Hence, option (a) is the correct option.
4. Amount spent on conveyance = 1 8 \dfrac{1}{8} 8 1 of the salary
= 1 8 × 60 , 000 = 1 × 60 , 000 8 = 60 , 000 8 = ₹ 7 , 500. = \dfrac{1}{8} \times 60,000 \\[1em] = \dfrac{1 \times 60,000}{8}\\[1em] = \dfrac{60,000}{8}\\[1em] = ₹7,500. = 8 1 × 60 , 000 = 8 1 × 60 , 000 = 8 60 , 000 = ₹7 , 500.
Hence, option (c) is the correct option.
A drum of kerosene is 3 4 \dfrac{3}{4} 4 3 full. When 30 litres of kerosene is drawn from it, it remains 7 12 \dfrac{7}{12} 12 7 full.
The capacity of the drum is : (a) 120 l (b) 150 l (c) 180 l (d) 168 l
The quantity of kerosene in the drum is : (a) 135 l (b) 115 l (c) 125 l (d) 108 l
If 15 l of kerosene is added to the drum, what fraction of the capacity would be filled?
(a) 1 2 \dfrac{1}{2} 2 1
(b) 2 3 \dfrac{2}{3} 3 2
(c) 5 6 \dfrac{5}{6} 6 5
(d) 5 12 \dfrac{5}{12} 12 5
If 35 l of kerosene is drawn from the drum, what fraction of the capacity would be filled? (a) 5 9 \dfrac{5}{9} 9 5
(b) 7 9 \dfrac{7}{9} 9 7
(c) 11 18 \dfrac{11}{18} 18 11
(d) 13 18 \dfrac{13}{18} 18 13
Answer
1. Given,
Initial capacity of drum = 3 4 \dfrac{3}{4} 4 3 full
After removing 30 litres: Capacity of drum = 7 12 \dfrac{7}{12} 12 7 full
Let the total capacity of drum be x litres.
⇒ 3 4 x − 30 = 7 12 x ⇒ 3 4 x − 7 12 x = 30 ⇒ 3 × 3 4 × 3 x − 7 12 x = 30 ⇒ 9 12 x − 7 12 x = 30 ⇒ 9 − 7 12 x = 30 ⇒ 2 12 x = 30 ⇒ 1 6 x = 30 ⇒ x = 30 × 6 ⇒ x = 180 l . \Rightarrow \dfrac{3}{4}x - 30 = \dfrac{7}{12}x\\[1em] \Rightarrow \dfrac{3}{4}x - \dfrac{7}{12}x = 30\\[1em] \Rightarrow \dfrac{3 \times 3}{4 \times 3}x - \dfrac{7}{12}x = 30\\[1em] \Rightarrow \dfrac{9}{12}x - \dfrac{7}{12}x = 30\\[1em] \Rightarrow \dfrac{9 - 7}{12}x = 30\\[1em] \Rightarrow \dfrac{2}{12}x = 30\\[1em] \Rightarrow \dfrac{1}{6}x = 30\\[1em] \Rightarrow x = 30 \times 6\\[1em] \Rightarrow x = 180 \text{ l}. ⇒ 4 3 x − 30 = 12 7 x ⇒ 4 3 x − 12 7 x = 30 ⇒ 4 × 3 3 × 3 x − 12 7 x = 30 ⇒ 12 9 x − 12 7 x = 30 ⇒ 12 9 − 7 x = 30 ⇒ 12 2 x = 30 ⇒ 6 1 x = 30 ⇒ x = 30 × 6 ⇒ x = 180 l .
Hence, option (c) is the correct option.
2. Initial quantity of kerosene = 3 4 \dfrac{3}{4} 4 3 of the capacity of drum
⇒ 3 4 × 180 ⇒ 3 × 180 4 ⇒ 540 4 ⇒ 135 \Rightarrow \dfrac{3}{4} \times 180\\[1em] \Rightarrow \dfrac{3 \times 180}{4}\\[1em] \Rightarrow \dfrac{540}{4}\\[1em] \Rightarrow 135 ⇒ 4 3 × 180 ⇒ 4 3 × 180 ⇒ 4 540 ⇒ 135
Hence, option (a) is the correct option.
3. If 15 l of kerosene is added to the drum.
So, final quantity of kerosene = 135 + 15 = 150
Fraction of drum filled = 150 180 = 5 6 \dfrac{150}{180} = \dfrac{5}{6} 180 150 = 6 5
Hence, option (c) is the correct option.
4. If 35 l of kerosene is drawn from the drum.
So, final quantity of kerosene = 135 - 35 = 100
Fraction of drum filled = 100 180 = 5 9 \dfrac{100}{180} = \dfrac{5}{9} 180 100 = 9 5 .
Hence, option (a) is the correct option.
Exercise 4(I) — Assertion-Reason Questions
Assertion (A): The sum of two fractions is always a fraction.
Reason (R): For two fractions a b and c d \dfrac{a}{b} \text{ and } \dfrac{c}{d} b a and d c , we have a b + c d = a d + b c b d \dfrac{a}{b} + \dfrac{c}{d} = \dfrac{ad + bc}{bd} b a + d c = b d a d + b c
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Assertion (A) is true but Reason (R) is false.
Assertion (A) is false but Reason (R) is true.
Answer
According to assertion; the sum of two fractions is always a fraction.
Example - the two fractions are 1 2 \dfrac{1}{2} 2 1 and 3 2 \dfrac{3}{2} 2 3
Now, 1 2 + 3 2 = 4 2 = 2 \dfrac{1}{2} + \dfrac{3}{2} = \dfrac{4}{2} = 2 2 1 + 2 3 = 2 4 = 2
∴ Assertion (A) is false.
For two fractions a b and c d \dfrac{a}{b} \text{and} \dfrac{c}{d} b a and d c , we have a b + c d \dfrac{a}{b} + \dfrac{c}{d} b a + d c
LCM of b and d = bd
a × d b × d + c × b d × b = a d b d + c b b d = a d + c b b d \dfrac{a \times d}{b \times d} + \dfrac{c \times b}{d \times b} = \dfrac{ad}{bd} + \dfrac{cb}{bd} = \dfrac{ad + cb}{bd} b × d a × d + d × b c × b = b d a d + b d c b = b d a d + c b
∴ Reason (R) is true.
Hence, option 4 is the correct option.
Assertion (A): Half of a number is obtained by dividing it by 2.
Reason (R): The fractions x y \dfrac{x}{y} y x and y x \dfrac{y}{x} x y are multiplicative inverse of each other.
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Assertion (A) is true but Reason (R) is false.
Assertion (A) is false but Reason (R) is true.
Answer
According to assertion, half of a number is obtained by dividing it by 2.
half of n is n 2 \dfrac{n}{2} 2 n , which is exactly dividing by 2.
∴ Assertion (A) is true.
According to reason, the fractions x y \dfrac{x}{y} y x and y x \dfrac{y}{x} x y are multiplicative inverse of each other.
⇒ x y × y x ⇒ x × y y × x ⇒ x × y y × x ⇒ 1. \Rightarrow \dfrac{x}{y} \times \dfrac{y}{x}\\[1em] \Rightarrow \dfrac{x \times y}{y \times x}\\[1em] \Rightarrow \dfrac{x \times y}{y \times x}\\[1em] \Rightarrow 1. ⇒ y x × x y ⇒ y × x x × y ⇒ y × x x × y ⇒ 1.
∴ Reason (R) is true.
∴ Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Hence, option 2 is the correct option.
Assertion (A): The sum of the fractions represented by the shaded and unshaded portion is 1.
Reason (R): We can only add like fractions.
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Assertion (A) is true but Reason (R) is false.
Assertion (A) is false but Reason (R) is true.
Answer
According to assertion, the sum of the fractions represented by the shaded and unshaded portion is 1.
Fraction of shaded portion = 5 9 \dfrac{5}{9} 9 5
Fraction of unshaded portion = 4 9 \dfrac{4}{9} 9 4
Sum of fraction of shaded portion + unshaded portion = 5 9 + 4 9 = 5 + 4 9 = 9 9 = 1 \dfrac{5}{9} + \dfrac{4}{9} = \dfrac{5 + 4}{9} = \dfrac{9}{9} = 1 9 5 + 9 4 = 9 5 + 4 = 9 9 = 1 .
∴ Assertion (A) is true.
According to reason, we can only add like fractions.
We can add any fractions (like or unlike), but if they are unlike fractions we first convert them to like fractions (common denominator) and then add.
∴ Reason (R) is false.
Hence, option 3 is the correct option.