The 7th term of the given Arithmetic Progression (A.P.):
is :
Answer
In the A.P. :
First term (x) =
Common difference (d) = = 1.
x7 = x + (7 - 1)d
=
= .
Hence, Option 1 is the correct option.
The nth term from the end of an A.P., whose first term, last term and common difference are a, l and d respectively, is given by:
l + (n + 1)d
l − (n − 1)d
l + (n − 1)d
l − (n + 1)d
Answer
Since, we need to calculate term from end.
So, first term will be equal to last term and common difference will be negative of the original difference.
∴ Tend = l + (n - 1)(-d)
= l - (n - 1)d.
Hence, option 2 is the correct option.
The sum of first n natural numbers is:
Answer
The sequence of natural numbers 1, 2, 3,....., n.
a = 1
l = n
no. of terms = n
Sum of n terms of an A.P. is given by,
∴ Sn = (a + l)
= (1 + n)
=
Hence, option 2 is the correct option.
The sum of first 50 natural numbers is:
1050
1175
1225
1275
Answer
Sequence : 1, 2, 3, ......, 50.
First term (a) = 1
Common difference (d) = 2 - 1 = 1
By formula,
Sum of n terms =
Hence, option 4 is the correct option.
The nth term of an Arithmetic Progression (A.P.) is 2n + 5. The 10th term is :
7
15
25
45
Answer
Given,
nth term of A.P. :
∴ Tn = 2n + 5
⇒ T10 = 2(10) + 5
= 20 + 5
= 25.
Hence, option 3 is the correct option.
The first term of an A.P. is 7 and the common difference is 3. The general term of the A.P. is:
Tn = 3n − 4
Tn = 2n + 5
Tn = 3n + 4
None of these
Answer
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
Given,
a = 7, d = 3
Tn = 7 + (n - 1)3
= 7 + 3n - 3
= 3n + 4.
Hence, option 3 is the correct option.
The 24th term of the A.P. −1, 3, 7, 11, … is:
83
87
91
95
Answer
The given Arithmetic Progression (A.P.) is
-1, 3, 7, 11,.....
a = -1
d = 3 - (-1) = 4
n = 24
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
⇒ T24 = -1 + (24 - 1)(4)
= -1 + (23)4
= -1 + 92
= 91.
Hence, option 3 is the correct option.
If 70, 75, 80, 85 are the first four terms of an arithmetic progression, then the 10th term is:
35
25
115
105
Answer
The given Arithmetic Progression (A.P.) is
70, 75, 80, 85, ....
a = 70
d = 75 - 70 = 5
n = 10
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
⇒ T10 = 70 + (10 - 1)5
= 70 + (9)5
= 70 + 45
= 115.
Hence, option 3 is the correct option.
The A.P. 6, 13, 20, …, 216 has 31 terms. The middle term of the A.P. is :
91
97
107
111
Answer
Given,
A.P. 6, 13, 20, …, 216
n = 31
Middle term of A.P. =
=
=
= 16th term.
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
Now we have,
a = 6
d = 13 - 6 = 7
n = 16
⇒ T16 = 6 + (16 - 1)(7)
= 6 + (15)7
= 6 + 105
= 111.
Hence, option 4 is the correct option.
Which term of the A.P. 7, 13, 19, 25,..... is 241?
40th
36th
44th
45th
Answer
Given,
A.P. : 7, 13, 19, 25,.......
a = 7
d = 13 - 7 = 6
Let nth term be 241.
Tn = 241
⇒ a + (n - 1)d = 241
⇒ 241 = 7 + (n - 1)6
⇒ 241 - 7 = (n - 1)6
⇒ 234 = (n - 1)6
⇒ = n - 1
⇒ n - 1 = 39
⇒ n = 39 + 1
⇒ n = 40.
Hence, option 1 is the correct option.
Which term of the A.P. 11, 8, 5, 2, ..... is −148 ?
52nd
54th
55th
57th
Answer
Given,
A.P. : 11, 8, 5, 2, .......
a = 11
d = 8 - 11 = -3
Let nth term of the A.P. be -148.
Tn = -148
⇒ a + (n - 1)d = -148
⇒ -148 = 11 + (n - 1)(-3)
⇒ -148 - 11 = (n - 1)(-3)
⇒ -159 = (n - 1)(-3)
⇒ = n - 1
⇒ n - 1 = 53
⇒ n = 53 + 1
⇒ n = 54.
Hence, option 2 is the correct option.
How many three-digit numbers are divisible by 7?
128
124
136
132
Answer
The three-digit numbers divisible by 7 form an Arithmetic Progression (A.P.) :
105, 112, 119, ......,994.
a = 105
l = 994
d = 7
Let no. of terms be n.
∴ Tn = a + (n - 1)d
⇒ 994 = 105 + (n - 1)7
⇒ 994 - 105 = (n - 1)7
⇒ 889 = (n - 1)7
⇒ = n - 1
⇒ 127 = n - 1
⇒ n = 127 + 1
⇒ n = 128.
Hence, option 1 is the correct option.
How many numbers lying between 20 and 200 are divisible by 4?
43
44
45
46
Answer
The numbers divisible by 4 lying between 20 and 200 form an Arithmetic Progression (A.P.).
24, 28, ....., 196.
a = 24
l = 196
d = 4
Let no. of terms be n.
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
⇒ 196 = 24 + (n - 1)4
⇒ 196 - 24 = (n - 1)4
⇒ 172 = (n - 1)4
⇒ = n - 1
⇒ 43 = n - 1
⇒ n = 43 + 1
⇒ n = 44.
Hence, option 2 is the correct option.
The common difference of the A.P. , ...... is :
−k
k
1
−1
Answer
Given,
A.P. : .........
a =
Hence, option 4 is the correct option.
If the nth term of an A.P. is given by (3n + 2), then the sum of its first three terms is :
21
24
27
32
Answer
The nth term of the A.P. is given by,
Tn = 3n + 2
T1 = 3(1) + 2 = 5
T2 = 3(2) + 2 = 8
T3 = 3(3) + 2 = 11
Sum = 5 + 8 + 11 = 24.
Hence, option 2 is the correct option.
The last term of the A.P., 5, 12, 19, ..... having 60 terms is :
406
412
416
418
Answer
Given,
A.P. : 5, 12, 19, .......
a = 5
d = 12 - 5 = 7
n = 60
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
⇒ T60 = 5 + (60 - 1)7
= 5 + (59) × 7
= 5 + 413
= 418.
Hence, option 4 is the correct option.
The common difference of the A.P. : , ... is:
p
−p
Answer
In the above A.P.,
Hence, option 2 is the correct option.
The next term of the A.P. , ... is:
Answer
In the above A.P. next terms is the 5th term.
a =
n = 5
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
Hence, option 3 is the correct option.
The first term of an A.P. is p and its common difference is q. The 10th term of the A.P. is :
p − 9q
p + 10q
p − 10q
p + 9q
Answer
Given,
First term = p
Common difference = q
n = 10
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
⇒ T10 = p + (10 - 1)q
= p + 9q.
Hence, option 4 is the correct option.
The nth term of the A.P. , ... is:
None of these
Answer
Given,
a =
We know that,
nth term of A.P. :
∴ Tn = a + (n - 1)d
Hence, option 1 is the correct option.
For what value of p are 2p + 1, 13, 5p − 3 three consecutive terms of an A.P. ?
0
1
2
4
Answer
Given,
2p + 1, 13, 5p − 3
In an A.P., the middle term is the average of the first and third terms.
Hence, option 4 is the correct option.
For what value of k will 2k + 1, 3k + 3, and 5k − 1 be three consecutive terms of an A.P.?
1
2
4
6
Answer
We are given three consecutive terms of an A.P.:
2k + 1, 3k + 3, 5k − 1
In an arithmetic progression, the difference between consecutive terms is the same.
⇒ (3k + 3) - (2k + 1) = (5k - 1) - (3k + 3)
⇒ 3k + 3 - 2k - 1 = 5k - 1 - 3k - 3
⇒ k + 2 = 2k - 4
⇒ 2 + 4 = 2k - k
⇒ k = 6.
Hence, option 4 is the correct option.
If the sum of first n terms of an A.P. is Sn = 5n2 + 3n, then its common difference is:
8
10
18
26
Answer
Given,
Sn = 5n2 + 3n
We know that,
nth term of A.P. :
∴ Tn = Sn - Sn - 1
= 5n2 + 3n - [5(n - 1)2 + 3(n - 1)]
= 5n2 + 3n - [5(n2 - 2n + 1) + 3n - 3]
= 5n2 + 3n - [5n2 - 10n + 5 + 3n - 3]
= 5n2 + 3n - 5n2 + 10n - 5 - 3n + 3
= 10n - 2
d = an - an - 1
= 10n - 2 - [10(n - 1) - 2]
= 10n - 2 - [10n - 10 - 2]
= 10n - 2 - 10n + 10 + 2
= 10.
Hence, option 2 is the correct option.
The first and the last terms of an A.P. are 1 and 11 respectively. If the sum of its terms is 36, then the number of terms is :
6
7
8
9
Answer
Given,
a = 1
l = 11
Let no. of terms be n.
Sn = 36
We know that,
⇒ Sn = (a + l)
⇒ 36 = (1 + 11)
⇒ 36 × 2 = n(12)
⇒ n =
⇒ n = 6.
Hence, option 1 is the correct option.
The sum of first 40 positive integers divisible by 6 is :
2460
3640
4920
4860
Answer
Sequence :
6, 12, 18, ......., upto 40th term.
The above sequence is an A.P. with,
a = 6
d = 6
n = 40
We know that,
Sn = [2a + (n - 1)d]
⇒ S40 = [2(6) + (40 - 1)6]
= 20[12 + (39)6]
= 20(12 + 234)
= 20 × (246)
= 4920.
Hence, option 3 is the correct option.
The sum of first 30 odd natural numbers is:
800
900
729
1249
Answer
1, 3, 5, 7, ......, 30th term.
The odd natural numbers form an Arithmetic Progression (A.P.) :
a = 1
d = 3 - 1 = 2
n = 30
We know that,
Sn = [2a + (n - 1)d]
⇒ S30 = [2(1) + (30 - 1)2]
= 15[2 + (29)2]
= 15[2 + 58]
= 15 × (60)
= 900.
Hence, option 2 is the correct option.
The 7th term of an A.P. is 4 and its common difference is −4. The first term of the A.P. is :
32
28
24
36
Answer
Given,
a7 = 4
d = -4
n = 7
We know that,
⇒ an = a + (n - 1)d
⇒ a7 = a + (7 - 1)(-4)
⇒ 4 = a + (6)(-4)
⇒ 4 = a - 24
⇒ 24 + 4 = a
⇒ a = 28.
Hence, option 2 is the correct option.
The sum of first n terms of an A.P. is (4n2 + 2n). The nth term of the A.P. is :
(6n − 2)
(8n − 2)
(6n + 2)
(8n + 2)
Answer
We know that,
Sn = 4n2 + 2n
Tn = Sn - Sn - 1
= 4n2 + 2n - [4(n - 1)2 + 2(n - 1)]
= 4n2 + 2n - [4(n2 - 2n + 1) + 2n - 2]
= 4n2 + 2n - [4n2 - 8n + 4 + 2n - 2]
= 4n2 + 2n -[4n2 - 6n + 2]
= 4n2 + 2n - 4n2 + 6n - 2
= 8n - 2.
Hence, option 2 is the correct option.
The first term of an A.P. is 7 and its 13th term is 35. The common difference of the A.P. is :
Answer
Given,
a = 7
⇒ a13 = 35
⇒ a + (13 - 1)d = 35
⇒ 7 + 12d = 35
⇒ 12d = 35 - 7
⇒ 12d = 28
⇒ d =
⇒ d = .
Hence, option 4 is the correct option.
There are total 9 terms in an A.P. If the last term and the sum of all the terms are 28 and 144 respectively, then the first term is :
1
7
4
5
Answer
We know that,
Sn = (a + l)
Given,
n = 9
l = 28
Sn = 144
⇒ S9 = (a + 28)
⇒ 144 = (a + 28)
⇒ = (a + 28)
⇒ 32 = (a + 28)
⇒ 32 - 28 = a
⇒ a = 4.
Hence, option 3 is the correct option.
The 5th term of an A.P. is −3 and its common difference is −4. The sum of its first 10 terms is :
−50
−40
−60
−30
Answer
Given,
a5 = -3
d = -4
n = 10
We know that,
⇒ an = a + (n - 1)d
⇒ a5 = a + (5 - 1)(-4)
⇒ -3 = a + (4)(-4)
⇒ -3 = a - 16
⇒ a = 16 - 3
⇒ a = 13.
We know that,
⇒ Sn = [2a + (n - 1)d]
⇒ S10 = [2(13) + (10 - 1)(-4)]
= 5[26 + (9)(-4)]
= 5[26 - 36]
= 5(-10)
= -50.
Hence, option 1 is the correct option.
The 7th term of an A.P. is −1 and its 16th term is 17. The nth term of the A.P. is :
(3n + 12)
(2n − 5)
(3n + 5)
(2n − 15)
Answer
We know that,
an = a + (n - 1)d
The 7th term of an A.P. is −1.
a + 6d = -1 ......(1)
The 16th term of an A.P. is 17.
a + 15d = 17 ......(2)
Subtract Equation (1) from Equation (2) :
⇒ a + 15d - (a + 6d) = 17 - (-1)
⇒ a + 15d - a - 6d = 18
⇒ 9d = 18
⇒ d =
⇒ d = 2.
Substituting d = 2 into Equation (1), we get :
⇒ a + 6(2) = -1
⇒ a + 12 = -1
⇒ a = -1 - 12
⇒ a = -13.
Now,
⇒ an = a + (n - 1)d
⇒ an = -13 + (n - 1)2
= -13 + 2n - 2
= 2n - 15.
Hence, option 4 is the correct option.
If the sum of first p terms of an A.P. is ap2 + bp, then its common difference is :
a
3a + b
a + b
2a
Answer
Given,
⇒ Sp = ap2 + bp
⇒ Tp = Sp - Sp - 1
= ap2 + bp - [a(p - 1)2 + b(p - 1)]
= ap2 + bp - [a(p2 - 2p + 1) + bp - b]
= ap2 + bp - [ap2 - 2ap + a + bp - b]
= ap2 + bp - ap2 + 2ap - a - bp + b
= 2ap - a + b.
d = Tp - Tp - 1
= 2ap - a + b - [2a(p - 1) - a + b]
= 2ap - a + b - [2ap - 2a - a + b]
= 2ap - a + b - 2ap + 2a + a - b
= 2a.
Hence, option 4 is the correct option.
The first term of an A.P. is a and nth term is b, then the common difference of the A.P. is :
Answer
Given,
First term = a
nth term = b
We know that,
an = a + (n - 1)d
⇒ b = a + (n - 1)d
⇒ b - a = (n - 1)d
⇒ d = .
Hence, option 2 is the correct option.
The first three terms of an A.P. are 3y − 1, 3y + 5 and 5y + 1 respectively. Then, the value of y is :
1
5
8
3
Answer
Given,
The first three terms of an A.P. are 3y − 1, 3y + 5 and 5y + 1.
The difference between consecutive terms must be equal.
⇒ 3y + 5 - (3y - 1) = 5y + 1 - (3y + 5)
⇒ 3y + 5 - 3y + 1 = 5y + 1 - 3y - 5
⇒ 6 = 2y - 4
⇒ 2y = 6 + 4
⇒ 2y = 10
⇒ y =
⇒ y = 5.
Hence, option 2 is the correct option.
The 8th term from the end of the A.P. 7, 10, 13, ..., 184 is:
157
160
163
166
Answer
Given,
a = 7
d = 10 - 7 = 3
an = 184
We know that,
⇒ an = a + (n - 1)d
⇒ an = 7 + (n - 1)(3)
⇒ 184 = 7 + (n - 1)(3)
⇒ 184 - 7 = (n - 1)(3)
⇒ 177 = (n - 1)(3)
⇒ = (n - 1)
⇒ n - 1 = 59
⇒ n = 59 + 1
⇒ n = 60.
The 8th term from the end is the (n - 8 + 1)th term from the beginning.
= 60 - 8 + 1
= 53.
⇒ a53 = 7 + (53 - 1)3
= 7 + (52)(3)
= 7 + 156
= 163.
Hence, option 3 is the correct option.
If a = 3, n = 8 and Sn = 192, then the common difference of the A.P. is:
4
5
6
7
Answer
a = 3
n = 8
Sn = 192
Sn = [2a + (n - 1)d]
⇒ 192 = [2(3) + (8 - 1)d]
⇒ 192 = 4[6 + 7d]
⇒ = [6 + 7d]
⇒ 48 = [6 + 7d]
⇒ 48 - 6 = 7d
⇒ 42 = 7d
⇒ d =
⇒ d = 6.
Hence, option 3 is the correct option.
If the sum of n terms of an arithmetic progression Sn = n2 - n, then the third term of the series is :
2
4
6
9
Answer
Given,
Sum of n terms of an arithmetic progression Sn = n2 - n.
S1 = 12 - 1 = 0,
S2 = 22 - 2 = 4 - 2 = 2,
S3 = 32 - 3 = 9 - 3 = 6.
Sum upto first term = First term = 0.
Given, sum upto 2 terms = 2 and first term = 0, second term = 2.
Sum upto third term = 6
∴ First term + Second term + Third term = 6
⇒ 0 + 2 + Third term = 6
⇒ Third term = 6 - 2 = 4.
Hence, Option 2 is the correct option.