Series Completion Interview Questions and Answers
Question - 61 : - 3, 7, 15, ?, 63, 127
A. 30
B. 31
C. 47
D. 52
Answer - 61 : -
Option B
Explanation:
Each number in the series is one more than twice the preceding number.
So, missing term = (15 x 2) + 1 = 31.
Question - 62 : - 45, 54, 47, ?, 49, 56, 51, 57, 53
A. 48
B. 50
C. 55
D. None of these
Answer - 62 : -
Option C
Explanation:
The given sequence is a combination of two series:
I. 45, 47, 49, 51, 53 and II. 54, ?, 56, 57
Clearly, II consists of consecutive natural numbers, starting from 54.
So, missing term = 55.
Question - 63 : - 3, 8, 13, 24, 41, ?
A. 70
B. 75
C. 80
D. 85
Answer - 63 : -
Option A
Explanation:
The pattern followed is : nth term + (n + l)th term + (n + 1) = (n + 2)th term.
Thus, 1st term + 2nd term + 2 = 3rd term; 2nd term + 3rd term + 3 = 4th term and so on.
So, missing term = 6th term = 4th term + 5th term + 5 = 24 + 41 + 5 = 70.
Question - 64 : - 10, 14, 26, 42, 70, ?
A. 100
B. 102
C. 106
D. 114
Answer - 64 : -
Option D
Explanation:
Each term in the series, except the first two terms, is 2 more than the sum of the preceding two terms.
So, missing term = (42 + 70) + 2 = 114.
Question - 65 : - 10, 18, 28, 40, 54, 70, ?
A. 85
B. 86
C. 87
D. 88
Answer - 65 : -
Option D
Explanation:
The pattern is + 8, + 10, + 12, + 14, .....
So, missing term = 70 + 18 = 88.
Question - 66 : - 8, 28, 116, 584, ?
A. 1752
B. 3502
C. 3504
D. 3508
Answer - 66 : -
Option D
Explanation:
The pattern is x 3 + 4, x 4 + 4, x 5 + 4,.....
So, missing term = 584 x 6 + 4 = 3508.
Question - 67 : - 3, 7, 23, 95, ?
A. 62
B. 128
C. 479
D. 575
Answer - 67 : -
Option C
Explanation:
The pattern is x 2 + 1, x 3 + 2, x 4 + 3,.....
So, missing term = 95 x 5 + 4 = 479.
Question - 68 : - 6, 18, 3, 21, 7, 56, ?
A. 8
B. 9
C. 63
D. 64
Answer - 68 : -
Option A
Explanation:
Each term at an even place in the series is the product of its two adjacent terms.
Thus, if the missing term be x, then we have : 7 x x = 56 or x = 56 รท 7 = 8.
Question - 69 : - 4, 9, 25, ?, 121, 169, 289, 361
A. 49
B. 64
C. 81
D. 87
Answer - 69 : -
Option A
Explanation:
The given series consists of squares of consecutive prime numbers
i.e. 22, 32, 52,.....,
112, 132, 172, 192.
So, missing term = 72 = 49.
Question - 70 : - 121, 143, 165, 186, 209
A. 143
B. 165
C. 186
D. 209
Answer - 70 : -
Option C
Explanation:
Each term in the series is obtained by adding 22 to the preceding term.
So, 186 is wrong and must be replaced by (165 + 22) i.e. 187.