Practice MCQ Questions and Answer on Number Series Completion
51.
Find the missing term: 6, 13, 25, 51, 101. ?
(A) 201
(B) 202
(C) 203
(D) 205
Solution:
The pattern is x2+1,x2-1,x2+1,x2-1.x...................So, missing term =101x2+1=203
52.
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.
53.
Find the missing term: 4832, 5840, 6848, ?
(A) 7815
(B) 7846
(C) 7856
(D) 7887
Solution:
The pattern is + 1008. So, the missing term = 6848 + 1008 = 7856.
54.
What will come at the place of question mark ? 2, 3, 6, 15, ?, 123
(A) 47
(B) 42
(C) 45
(D) 50
Solution:
First term → 2 Second term → (2 *3 -3) = 3 Third term → (3 *3 -3) = 6 Fourth term → (6 *3 - 3) = 15 Fifth term → (15 *3 - 3) = 42 Sixth term → (42 *3 - 3) = 123
The given series is a triangular pattern series.So, we have Series I : 2 9 28 ? 126 217 344 Series II : 7 19 ? ? 91 127 Series III : 12 ? ? ? 36 Clearly, to form a pattern, the missing terms in Series III must be 18, 24, 30So, missing term = 127 + (61 + 24 + 6)= 127 + 91= 218
56.
Find out the wrong term: 1, 5, 5, 9, 7, 11, 11, 15, 12, 17
(A) 11
(B) 12
(C) 17
(D) 15
Solution:
The given sequence is a combination of two series :I: 1, 5, 7, 11, 12 and II: 5, 9, 11, 15, 17The pattern in both I and II is + 4, + 2, + 4, + 2, So, 12 is wrong and must be replaced by (11 + 2) i.e., 13.
57.
Find the missing number: 111/9, 121/2, 142/7, 162/3, ?
(A) 81/3
(B) 191/2
(C) 20
(D) 221/3
Solution:
The given sequence is 100/9 , 25/2 , 100/7 , 50/3, ............i.e., 100/9, 100/8, 100/7, 100/6.................So, missing term = 100/5 = 20
58.
84, 78, 72, 66, 60, 54, 48, ... choose which pair of numbers comes next?
(A) 44, 34
(B) 42, 36
(C) 42, 32
(D) 40, 34
Solution:
In this simple subtraction series, each number is 6 less than the previous number.
59.
Find out the wrong term: 121, 143, 165, 186, 209
(A) 143
(B) 165
(C) 186
(D) 209
Solution:
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.
60.
Find the missing term: 13, 35, 57, 79, 911, ?
(A) 1110
(B) 1112
(C) 1113
(D) 1315
Solution:
The term of the given series are numbers formed by joining together consecutive odd numbers in order i.e., 1 and 3, 3 and 5, 5 and 7, 7 and 9, 9 and 11...................So, missing term = number formed by joining 11 and 13 = 1113