Practice MCQ Questions and Answer on Number Series Completion
81.
Find the missing term: 4, 6, 9, 131/2, ?
(A) 171/2
(B) 19
(C) 201/4
(D) 223/4
Solution:
The pattern is × 3/2.So, missing number = 131/2 × 3/2 = 27/2 × 3/2 = 81/4 = 201/4.
82.
9, 11, 33, 13, 15, 33, 17, ... choose which pair of numbers comes next?
(A) 19, 33
(B) 33, 35
(C) 33, 19
(D) 15, 33
Solution:
In this alternating repetition series, a random number, 33, is interpolated every third number into a simple addition series, in which each number increases by 2.
83.
32, 31, 32, 29, 32, 27, 32, ... choose which pair of numbers comes next?
(A) 25, 32
(B) 31, 32
(C) 29, 32
(D) 25, 30
Solution:
This is an alternating repetition series. The number 32 alternates with a series in which each number decreases by 2.
84.
Find out the wrong term: 3, 7, 15, 39, 63, 127, 255, 511
(A) 15
(B) 39
(C) 63
(D) 127
Solution:
The correct pattern is × 2 + 1.So, 39 is wrong and must be replaced by (15 × 2 + 1) i.e., 31.
85.
21, 25, 18, 29, 33, 18, ... choose which pair of numbers comes next?
(A) 43, 18
(B) 41, 44
(C) 37, 18
(D) 37, 41
Solution:
This is a simple addition series with a random number, 18, interpolated as every third number. In the series, 4 is added to each number except 18, to arrive at the next number.
86.
Find out the wrong term: 2, 5, 10, 50, 500, 5000
(A) 5
(B) 10
(C) 50
(D) 5000
Solution:
Each term of the series is the product of the preceding two terms.So, 5000 is wrong and must be replaced by (50 × 500) = i.e., 25000
87.
Find out the wrong term: 325, 259, 202, 160, 127, 105, 94
(A) 94
(B) 127
(C) 202
(D) 259
Solution:
The correct pattern is - 66, - 55, - 44, - 33, - 22, - 11.So, 202 is wrong and must be replaced by (259 - 55) i.e., 204.
88.
Find the missing term: 2, 5, 9, ?, 20, 27
(A) 14
(B) 16
(C) 18
(D) 24
Solution:
The pattern is +3, +4, +5, +6,........So, missing term=9+5=14
89.
2, 8, 14, 20, 26, 32, 38, ... choose which pair of numbers comes next?
(A) 2, 46
(B) 44, 50
(C) 42, 48
(D) 40, 42
Solution:
This is a simple addition series, which begins with 2 and adds 6.
90.
6, 20, 8, 14, 10, 8, 12, ... choose which pair of numbers comes next?
(A) 14, 10
(B) 2, 18
(C) 4, 12
(D) 2, 14
Solution:
This is an alternating addition and subtraction series. In the first pattern, 2 is added to each number to arrive at the next; in the alternate pattern, 6 is subtracted from each number to arrive at the next.