Practice MCQ Questions and Answer on Number Series Completion
41.
Find the missing term: 22, 24, 28, ?, 52, 84
(A) 36
(B) 38
(C) 42
(D) 46
Solution:
The pattern is + 2, + 4, + 8, +16,............ So, the missing term = 28 + 8 = 36
42.
Find out the wrong term: 1, 3, 10, 21, 64, 129, 356, 777
(A) 21
(B) 129
(C) 10
(D) 356
Solution:
The correct pattern is × 2 + 1, × 3 + 1, × 2 + 1, × 3 + 1,...........So, 356 is wrong and must be replaced by (129 × 3 + 1) i.e., 388.
43.
80, 10, 70, 15, 60, ... What number should come next?
(A) 20
(B) 25
(C) 30
(D) 50
Solution:
This is an alternating addition and subtraction series. In the first pattern, 10 is subtracted from each number to arrive at the next. In the second, 5 is added to each number to arrive at the next.
44.
Find the missing term: 2, 7, 27, 107, 427, ?
(A) 1262
(B) 1707
(C) 4027
(D) 4207
Solution:
The pattern is +5, +20, +80, +320 i.e. +(5 × 12 ), +(5 × 22 ), +(5 × 42 ), +(5 × 82 ) So, missing term = 427 + +(5 × 162 ) = 427 +1280 = 1707
45.
Find the missing term: 28, 33, 31, 36, ?, 39
(A) 32
(B) 34
(C) 38
(D) 40
Solution:
The pattern is + 5, - 2, + 5, - 2,........ So, missing term = 36 - 2 = 34
46.
Find the missing number:- 0.5, 0.55, 0.65, 0.8, ?
(A) 0.9
(B) 0.82
(C) 1
(D) 0.95
Solution:
The pattern is + 0.05, + 0.10, + 0.15,................ So, missing term = 0.8 + 0.20 = 1
47.
In a given series one term is wrong or missing term: 1, 5, 11, 19, 29, 55
(A) 55
(B) 41
(C) 29
(D) 19
Solution:
The correct sequence is + 4, + 6, + 8, + 10, ............So, next term after 29 = 29 + 12 = 41.The term after 41 will then be (41 + 14) i.e., 55.∴ 41 is missing.
48.
What will come at the place of question mark ? 7, 11, 19, 35, 67, ?
(A) 99
(B) 131
(C) 137
(D) 124
Solution:
Logic: Last Term *2 - 3 = Next Term. First Term = 7 Second Term = 7 * 2 -3 = 11 Third Term = 11 * 2 - 3 = 19 Fourth Term = 19 * 2 - 3 = 35 Fifth Term = 35 * 2 - 3 = 67 Sixth Term = 67 * 2 -3 = 131 Alternative Solution : Last term + 2n = Next Term First Term = 7 Second Term = 7 + 22 = 11 Third Term = 11 + 23 = 19 Fourth Term = 19 + 24 = 35 Fifth Term = 35 + 25 = 67 Sixth Term = 67 + 26 = 131
49.
In a given series one term is wrong or missing term: 1, 5, 14, 30, 55, 93
(A) 97
(B) 95
(C) 93
(D) 55
Solution:
The correct pattern is + 4, + 9, + 16, + 25,+ 36 i.e., + 22, + 32 , + 42 , + 52 , + 62 So, 93 is wrong and must be replaced by (55 + 36) i.e., 91.
50.
21, 9, 21, 11, 21, 13, 21, ... What number should come next?
(A) 14
(B) 15
(C) 21
(D) 23
Solution:
In this alternating repetition series, the random number 21 is interpolated every other number into an otherwise simple addition series that increases by 2, beginning with the number 9.