Series Completion Interview Questions and Answers
Question - 11 : - 2,3,8,27, 112,?
A. 226
B. 339
C. 452
D. 565
Answer - 11 : -
Option D
Explanation:
The pattern is x 1 + 1, x 2 + 2, x 3 + 3, x 4 + 4,.....
So, missing term = 112 x 5 + 5 = 565.
Question - 12 : - 6, 17, 39, 72, ?
A. 83
B. 94
C. 116
D. 127
Answer - 12 : -
Option C
Explanation:
The pattern is + 11, + 22, + 33, .....
So, missing term = 72 + 44 = 116.
Question - 13 : - 20, 20, 19, 16, 17, 13, 14, 11, ?, ?
A. 10, 10
B. 10, 11
C. 13, 14
D. 13, 16
Answer - 13 : -
Option A
Explanation:
Let the missing terms of the series be x and y.
Thus, the sequence 20, 20, 19, 16, 17, 13, 14, 11, x ,y is a combination of two series :
I. 20, 19, 17, 14, x and II. 20, 16, 13, 11, y
The pattern in I is - 1, - 2, - 3,......So, missing term, x = 14 - 4 = 10.
The pattern in II is - 4, - 3, - 2,......So, missing term, y = 11 - 1 = 10.
Question - 14 : - 24, 60, 120, 210, ?
A. 300
B. 336
C. 420
D. 525
Answer - 14 : -
Option B
Explanation:
The pattern is + 36, + 60, + 90,.....i.e. + [6 x (6 + 0)], + [6 x (6 + 4)], + [6 x (6 + 9)],...
So, missing term = 210 + [6 x (6 + 15)] = 210 + 126 = 336.
Question - 15 : - 625, 5, 125, 25, 25, ?, 5
A. 5
B. 25
C. 125
D. 625
Answer - 15 : -
Option C
Explanation:
The given sequence is a combination of two series :
I. 625, 125, 25, 5 and II. 5, 25, ?
The pattern in I is ÷ 5, while that in II is x 5. So, missing term = 25 x 5 = 125.
Question - 16 : - 3, 4, 7, 7, 13, 13, 21, 22, 31, 34, ?
A. 42
B. 43
C. 51
D. 52
Answer - 16 : -
Option B
Explanation:
The given sequence is a combination of two series :
I. 3, 7, 13, 21, 31, ? and II. 4, 7, 13, 22, 34
The pattern in I is + 4, + 6, + 8, + 10,.....
The pattern in II is + 3, + 6, + 9, + 12,.....
So, missing term = 31 + 12 = 43.
Question - 17 : - 198, 194, 185, 169, ?
A. 92
B. 112
C. 136
D. 144
Answer - 17 : -
Option D
Explanation:
The pattern is - 4, - 9, - 16,.....i.e. - 22, - 32, - 42,.....
So, missing pattern = 169 - 52 = 169 - 25 = 144.
Question - 18 : - 2, 3, 5,7,11,?, 17
A. 12
B. 13
C. 14
D. 15
Answer - 18 : -
Option B
Explanation:
Clearly, the given series consists of prime numbers starting from 2. So, the missing
term is the prime number after 11, which is 13.
Question - 19 : - 6, 12, 21, ?, 48
A. 33
B. 38
C. 40
D. 45
Answer - 19 : -
Option A
Explanation:
The pattern is + 6, + 9, + 12, + 15, .....
So, missing term = 21 + 12 = 33.
Question - 20 : - Which term of the series 5, 10, 20, 40, ..... is 1280?
A. 10th
B. 9th
C. 8th
D. None of these
Answer - 20 : -
Option B
Explanation:
Clearly, 5 x 2 = 10, 10 x 2 = 20, 20 x 2 = 40,.....
So, the series is a G.P. in which a = 5 and r = 2.
Let 1280 be the rath term of the series.
Then, 5x2n-1 = 1280 2n-1 = 256 = 28 n - 1 = 8 n = 9.