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Chapter 2

Fractions - Exercise 2(C)

Class - 7 RS Aggarwal Mathematics Solutions



Exercise 2(C)

Question 1

Simplify :

123+561\dfrac{2}{3} + \dfrac{5}{6} of 2425\dfrac{24}{25}

Answer

We have:

123+561\dfrac{2}{3} + \dfrac{5}{6} of 2425\dfrac{24}{25}

= 53\dfrac{5}{3} + 56\dfrac{5}{6} of 2425\dfrac{24}{25} [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

=53+56×2425=53+16×245=53+2430=53+45[Of simplified]=25+1215=3715[Addition simplified]=2715[Converting improper to mixed fraction]\begin{array}{ll} = \dfrac{5}{3} + \dfrac{5}{6} \times \dfrac{24}{25} \\\\ = \dfrac{5}{3} + \dfrac{1}{6} \times \dfrac{24}{5} \\\\ = \dfrac{5}{3} + \dfrac{24}{30} \\\\ = \dfrac{5}{3} + \dfrac{4}{5} & \text{[Of simplified]} \\\\ = \dfrac{25 + 12}{15} = \dfrac{37}{15} & \text{[Addition simplified]} \\\\ = 2\dfrac{7}{15} & \text{[Converting improper to mixed fraction]} \end{array}

∴ The answer is 27152\dfrac{7}{15}

Question 2

Simplify :

13\dfrac{1}{3} of 423÷213×1124\dfrac{2}{3} ÷ 2\dfrac{1}{3}\times 1\dfrac{1}{2}

Answer

We have:

13\dfrac{1}{3} of 4234\dfrac{2}{3} ÷ 213×1122\dfrac{1}{3}\times 1\dfrac{1}{2}

= 13\dfrac{1}{3} of 143\dfrac{14}{3} ÷ 73×32\dfrac{7}{3}\times \dfrac{3}{2} [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

=13×143÷73×32=1×143×3÷73×32=149÷73×32[Of simplified]=149×37×32[Reciprocal of 73 is 37]=143×17×32=23×11×32=2×13×1×32=23×32[Division simplified]=2×33×2=66=11=1[Multiplication simplified]\begin{array}{ll} = \dfrac{1}{3} \times \dfrac{14}{3} ÷ \dfrac{7}{3}\times \dfrac{3}{2} \\\\ = \dfrac{1 \times 14}{3 \times 3} ÷ \dfrac{7}{3}\times \dfrac{3}{2} \\\\ = \dfrac{14}{9} ÷ \dfrac{7}{3}\times \dfrac{3}{2} & \text{[Of simplified]} \\\\ = \dfrac{14}{9} \times \dfrac{3}{7}\times \dfrac{3}{2} & [\text{Reciprocal of } \dfrac{7}{3} \text{ is } \dfrac{3}{7}] \\\\ = \dfrac{14}{3} \times \dfrac{1}{7} \times \dfrac{3}{2} \\\\ = \dfrac{2}{3} \times \dfrac{1}{1} \times \dfrac{3}{2} \\\\ = \dfrac{2 \times1}{3 \times 1} \times \dfrac{3}{2} = \dfrac{2}{3} \times \dfrac{3}{2} & \text{[Division simplified]} \\\\ = \dfrac{2 \times 3}{3 \times 2} = \dfrac{6}{6}\\\\ = \dfrac{1}{1} = 1 & \text{[Multiplication simplified]} \end{array}

∴ The answer is 1

Question 3

Simplify :

214+116123÷2232\dfrac{1}{4} + 1\dfrac{1}{6} - 1\dfrac{2}{3} ÷ 2\dfrac{2}{3} of 3343\dfrac{3}{4}

Answer

We have:

214+116123÷2232\dfrac{1}{4} + 1\dfrac{1}{6} - 1\dfrac{2}{3} ÷ 2\dfrac{2}{3} of 3343\dfrac{3}{4}

= 94\dfrac{9}{4} + 76\dfrac{7}{6} - 53\dfrac{5}{3} ÷ 83\dfrac{8}{3} of 154\dfrac{15}{4} [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

=94+7653÷83×154=94+7653÷8×153×4=94+7653÷12012=94+7653÷101[Of simplified]=94+7653×110[Reciprocal of 101 is 110]=94+765×13×10=94+76530=94+7616=27+141216=411216[Addition simplified]=41212=3912=134[Subtraction simplified]=314[Converting improper to mixed fraction]\begin{array}{ll} = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5}{3} ÷ \dfrac{8}{3}\times \dfrac{15}{4} \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5}{3} ÷ \dfrac{8 \times 15}{3 \times 4} \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5}{3} ÷ \dfrac{120}{12} \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5}{3} ÷ \dfrac{10}{1} & \text{[Of simplified]} \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5}{3} \times \dfrac{1}{10} & [\text{Reciprocal of } \dfrac{10}{1} \text{ is } \dfrac{1}{10}] \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5 \times 1}{3 \times 10} \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{5}{30} \\\\ = \dfrac{9}{4} + \dfrac{7}{6} - \dfrac{1}{6} \\\\ = \dfrac{27 + 14}{12} - \dfrac{1}{6} \\\\ = \dfrac{41}{12} - \dfrac{1}{6} & \text{[Addition simplified]} \\\\ = \dfrac{41 - 2}{12} \\\\ = \dfrac{39}{12} \\\\ = \dfrac{13}{4} & \text{[Subtraction simplified]} \\\\ = 3\dfrac{1}{4} & \text{[Converting improper to mixed fraction]} \\\\ \end{array}

∴ The answer is 3143\dfrac{1}{4}

Question 4

Simplify :

112×234÷1471\dfrac{1}{2}\times2\dfrac{3}{4} ÷ 1\dfrac{4}{7} of 2582\dfrac{5}{8}

Answer

We have:

112×234÷1471\dfrac{1}{2}\times2\dfrac{3}{4} ÷ 1\dfrac{4}{7} of 2582\dfrac{5}{8}

= 32×114\dfrac{3}{2}\times \dfrac{11}{4} ÷ 117\dfrac{11}{7} of 218\dfrac{21}{8} [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

=32×114÷117×218=32×114÷111×38=32×114÷11×31×8=32×114÷338[Of simplified]=32×114×833[Reciprocal of 338 is 833]=32×14×83=32×11×23=32×1×21×3=32×23[Division simplified]=66=1[Multiplication simplified]\begin{array}{ll} = \dfrac{3}{2}\times \dfrac{11}{4} ÷ \dfrac{11}{7} \times \dfrac{21}{8} \\\\ = \dfrac{3}{2}\times \dfrac{11}{4} ÷ \dfrac{11}{1} \times \dfrac{3}{8} \\\\ = \dfrac{3}{2}\times \dfrac{11}{4} ÷ \dfrac{11 \times 3}{1 \times 8} \\\\ = \dfrac{3}{2}\times \dfrac{11}{4} ÷ \dfrac{33}{8} & \text{[Of simplified]} \\\\ = \dfrac{3}{2}\times \dfrac{11}{4} \times \dfrac{8}{33} & [\text{Reciprocal of } \dfrac{33}{8} \text{ is } \dfrac{8}{33}] \\\\ = \dfrac{3}{2}\times \dfrac{1}{4} \times \dfrac{8}{3} \\\\ = \dfrac{3}{2}\times \dfrac{1}{1} \times \dfrac{2}{3}\\\\ = \dfrac{3}{2}\times \dfrac{1 \times 2}{1 \times 3} \\\\ = \dfrac{3}{2}\times \dfrac{2}{3} & \text{[Division simplified]} \\\\ = \dfrac{6}{6} = 1 & \text{[Multiplication simplified]} \\\\ \end{array}

∴ The answer is 1

Question 5

Simplify :

(234+156)\Big(2\dfrac{3}{4} + 1\dfrac{5}{6}\Big) ÷ 2152\dfrac{1}{5} of 3133\dfrac{1}{3}

Answer

We have:

(234+156)\Big(2\dfrac{3}{4} + 1\dfrac{5}{6}\Big) ÷ 2152\dfrac{1}{5} of 3133\dfrac{1}{3}

= (114+116)\Big(\dfrac{11}{4} + \dfrac{11}{6}\Big) ÷ 115\dfrac{11}{5} of 103\dfrac{10}{3} [Converting mixed to improper fraction]

According to BODMAS rule, we simplify brackets first

=(33+2212)÷115 of 103=5512÷115 of 103[Brackets simplified]=5512÷115×103=5512÷11015=5512÷223[Of simplified]=5512×322[Reciprocal of 223 is 322]=512×32[Dividing 55 and 22 by 11]=1524=58[Division simplified]\begin{array}{ll} = \Big(\dfrac{33 + 22}{12}\Big) ÷ \dfrac{11}{5} \text{ of } \dfrac{10}{3} \\\\ = \dfrac{55}{12} ÷ \dfrac{11}{5} \text{ of } \dfrac{10}{3} & \text{[Brackets simplified]} \\\\ = \dfrac{55}{12} ÷ \dfrac{11}{5} \times \dfrac{10}{3} \\\\ = \dfrac{55}{12} ÷ \dfrac{110}{15} \\\\ = \dfrac{55}{12} ÷ \dfrac{22}{3} & \text{[Of simplified]} \\\\ = \dfrac{55}{12} \times \dfrac{3}{22} & [\text{Reciprocal of } \dfrac{22}{3} \text{ is } \dfrac{3}{22}] \\\\ = \dfrac{5}{12} \times \dfrac{3}{2} & \text{[Dividing 55 and 22 by 11]} \\\\ = \dfrac{15}{24} = \dfrac{5}{8} & \text{[Division simplified]} \end{array}

∴ The answer is 58\dfrac{5}{8}

Question 6

Simplify :

715\dfrac{7}{15} of (23+712)\Big(\dfrac{2}{3} + \dfrac{7}{12}\Big) ÷ (5635)\Big(\dfrac{5}{6}-\dfrac{3}{5}\Big)

Answer

We have:

715\dfrac{7}{15} of (23+712)\Big(\dfrac{2}{3} + \dfrac{7}{12}\Big) ÷ (5635)\Big(\dfrac{5}{6}-\dfrac{3}{5}\Big)

According to BODMAS rule, we simplify brackets first

=715 of (8+712)÷(5635)=715 of (1512)÷(5635)=715 of 1512÷(5635)[First bracket simplified]=715 of 1512÷(251830)=715 of 1512÷730[Second bracket simplified]=715×1512÷730=712÷730[Of simplified]=712×307[Reciprocal of 730 is 307]=112×301[Dividing 7 and 7 by 7]=12×51[Dividing 30 and 12 by 6]=52[Division simplified]=212\begin{array}{ll} = \dfrac{7}{15}\text{ of }\Big(\dfrac{8 + 7}{12}\Big) ÷ \Big(\dfrac{5}{6}-\dfrac{3}{5}\Big) \\\\ = \dfrac{7}{15}\text{ of } \Big(\dfrac{15}{12}\Big) ÷ \Big(\dfrac{5}{6}-\dfrac{3}{5}\Big) \\\\ = \dfrac{7}{15}\text{ of } \dfrac{15}{12} ÷ \Big(\dfrac{5}{6}-\dfrac{3}{5}\Big) & \text{[First bracket simplified]} \\\\ = \dfrac{7}{15}\text{ of } \dfrac{15}{12} ÷ \Big(\dfrac{25 - 18}{30}\Big) \\\\ = \dfrac{7}{15}\text{ of } \dfrac{15}{12} ÷ \dfrac{7}{30} & \text{[Second bracket simplified]} \\\\ = \dfrac{7}{15} \times \dfrac{15}{12} ÷ \dfrac{7}{30} \\\\ = \dfrac{7}{12} ÷ \dfrac{7}{30} & \text{[Of simplified]} \\\\ = \dfrac{7}{12} \times \dfrac{30}{7} & [\text{Reciprocal of } \dfrac{7}{30} \text{ is } \dfrac{30}{7}] \\\\ = \dfrac{1}{12} \times \dfrac{30}{1} & \text{[Dividing 7 and 7 by 7]} \\\\ = \dfrac{1}{2} \times \dfrac{5}{1} & \text{[Dividing 30 and 12 by 6]} \\\\ = \dfrac{5}{2} & \text{[Division simplified]} \\\\ = 2\dfrac{1}{2} \end{array}

∴ The answer is 2122\dfrac{1}{2}

Question 7

Simplify :

(22÷512)\Big(22÷5\dfrac{1}{2}\Big) ÷ 2152\dfrac{1}{5} of 313+15113\dfrac{1}{3} + 1\dfrac{5}{11}

Answer

We have:

(22÷512)\Big(22÷5\dfrac{1}{2}\Big) ÷ 2152\dfrac{1}{5} of 313+15113\dfrac{1}{3} + 1\dfrac{5}{11}

= (22÷112)\Big(22÷\dfrac{11}{2}\Big) ÷ 115\dfrac{11}{5} of 103\dfrac{10}{3} + 1611\dfrac{16}{11} [Converting mixed to improper fraction]

According to BODMAS rule, we simplify brackets first

=(22×211)÷115 of 103+1611[Reciprocal of 112 is 211]=(4411)÷115 of 103+1611[Divide 44 and 11 by 11]=41÷115 of 103+1611[Bracket simplified]=41÷115×103+1611=41÷11015+1611[Divide 110 and 15 by 5]=41÷223+1611[Of simplified]=41×322+1611[Reciprocal of 223 is 322]=1222+1611[Divide 12 and 22 by 2]=611+1611[Division simplified]=6+1611=2211[Divide 22 and 11 by 11]=2[Division simplified]\begin{array}{ll} = \Big(22 \times \dfrac{2}{11}\Big) ÷ \dfrac{11}{5}\text{ of }\dfrac{10}{3} + \dfrac{16}{11} & [\text{Reciprocal of } \dfrac{11}{2} \text{ is } \dfrac{2}{11}] \\\\ = \Big(\dfrac{44}{11}\Big) ÷ \dfrac{11}{5}\text{ of }\dfrac{10}{3} + \dfrac{16}{11} & \text{[Divide 44 and 11 by 11]} \\\\ = \dfrac{4}{1} ÷ \dfrac{11}{5}\text{ of }\dfrac{10}{3} + \dfrac{16}{11} & \text{[Bracket simplified]} \\\\ = \dfrac{4}{1} ÷ \dfrac{11}{5} \times \dfrac{10}{3} + \dfrac{16}{11} \\\\ = \dfrac{4}{1} ÷ \dfrac{110}{15} + \dfrac{16}{11} & \text{[Divide 110 and 15 by 5]} \\\\ = \dfrac{4}{1} ÷ \dfrac{22}{3} + \dfrac{16}{11} & \text{[Of simplified]} \\\\ = \dfrac{4}{1} \times \dfrac{3}{22} + \dfrac{16}{11} & [\text{Reciprocal of } \dfrac{22}{3} \text{ is } \dfrac{3}{22}] \\\\ = \dfrac{12}{22} + \dfrac{16}{11} & \text{[Divide 12 and 22 by 2]} \\\\ = \dfrac{6}{11} + \dfrac{16}{11} & \text{[Division simplified]} \\\\ = \dfrac{6 + 16}{11} = \dfrac{22}{11} & \text{[Divide 22 and 11 by 11]} \\\\ = 2 & \text{[Division simplified]} \end{array}

∴ The answer is 2

Question 8

Simplify :

6136\dfrac{1}{3} ÷ (215+312)\Big(2\dfrac{1}{5} + 3\dfrac{1}{2}\Big) of 3133\dfrac{1}{3}

Answer

We have:

6136\dfrac{1}{3} ÷ (215+312)\Big(2\dfrac{1}{5} + 3\dfrac{1}{2}\Big) of 3133\dfrac{1}{3}

= 193\dfrac{19}{3} ÷ (115+72)\Big(\dfrac{11}{5} + \dfrac{7}{2}\Big) of 103\dfrac{10}{3} [Converting mixed to improper fraction]

According to BODMAS rule, we simplify brackets first

=193÷(22+3510) of 103=193÷5710 of 103[Bracket simplified]=193÷5710×103=193÷57030=193÷191[Of simplified]=193×119[Reciprocal of 191 is 119]=13[Division simplified]\begin{array}{ll} = \dfrac{19}{3} ÷ \Big(\dfrac{22 + 35}{10}\Big)\text{ of }\dfrac{10}{3} \\\\ = \dfrac{19}{3} ÷ \dfrac{57}{10}\text{ of }\dfrac{10}{3} & \text{[Bracket simplified]} \\\\ = \dfrac{19}{3} ÷ \dfrac{57}{10} \times \dfrac{10}{3} \\\\ = \dfrac{19}{3} ÷ \dfrac{570}{30} \\\\ = \dfrac{19}{3} ÷ \dfrac{19}{1} & \text{[Of simplified]} \\\\ = \dfrac{19}{3} \times \dfrac{1}{19} & [\text{Reciprocal of } \dfrac{19}{1} \text{ is } \dfrac{1}{19}] \\\\ = \dfrac{1}{3} & \text{[Division simplified]} \end{array}

∴ The answer is 13\dfrac{1}{3}

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