Practice MCQ Questions and Answer on Number Series Completion
121.
7, 10, 8, 11, 9, 12, ... What number should come next?
(A) 7
(B) 10
(C) 12
(D) 13
Solution:
This is a simple alternating addition and subtraction series. In the first pattern, 3 is added; in the second, 2 is subtracted. Alternate Solution : Above Series contains two sub series in it Series 1st = 7, 8, 9, 10 Series 2nd = 10, 11, 12 Note : Both sub series is in ascending order. Next number is greater by 1 from the previous one.
122.
Find the missing number:- 2, 15, 41, 80, ?
(A) 111
(B) 120
(C) 121
(D) 132
Solution:
The pattern is + 13, + 26, + 39,.... So, missing term = 80 + 52 = 132
123.
Which of the following will not be a number of the series 1, 8, 27, 64, 125, ....?
(A) 256
(B) 512
(C) 729
(D) 1000
Solution:
The given series consists of cubes of natural numbers only. 256 is not the cube of any natural number.
124.
What will come at the place of question mark ? 4, 8, 10, 14, 16, 20, ?
(A) 22
(B) 21
(C) 20
(D) 16
Solution:
Above series contains two sub-series in it. 4, 10, 16, 22 8, 14, 20 Each of both term there is difference of 6 i.e. next term is 6 greater than previous term.
125.
What will come at the place of question mark ? 113, 225, 449, ? , 1793
The given series consists of squares of consecutive prime numbers i.e., 22 , 32 , 52 ,.....................,112 , 132 , 172 , 192 So, missing term = 72 = 49
128.
Find out the wrong term: 2, 5, 10, 17, 26, 37, 50, 64
(A) 17
(B) 26
(C) 37
(D) 64
Solution:
The term of the series are (12 + 1)(22 + 1)(32 + 1)(42 + 1)(52 + 1)(62 + 1)(72 + 1),..............So, 64 is wrong and must be replaced by (82 + 1) i.e., 65
129.
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
130.
Find the missing term: 1, 5, 14, 30, 55, 91,?
(A) 130
(B) 140
(C) 150
(D) 160
Solution:
The pattern is + 4, + 9, + 6, + 25, + 36,........i.e.,+ 22 ,+ 32 + 42 + 52 + 62 ......... So, the missing term = 91 + 72 = 91+ 49 = 140