Practice MCQ Questions and Answer on Number Series Completion
81.
3, 5, 35, 10, 12, 35, 17, ... choose which pair of numbers comes next?
(A) 22, 35
(B) 35, 19
(C) 19, 35
(D) 19, 24
Solution:
This is an alternating addition series, with a random number, 35, interpolated as every third number. The pattern of addition is to add 2, add 5, add 2, and so on. The number 35 comes after each "add 2" step/
82.
In the series 2, 6, 18, 54, ...., what will be the 8th term ?
(A) 4370
(B) 4374
(C) 7443
(D) 7434
Solution:
Clearly, 2 × 3 = 6, 6 × 3 = 18, 18 × 3 = 54,..............S, the series is a G.P. in which a = 2, r = 3∴8th term = ar(8 - 1)= ar7 = 2 × 37 = (2 × 2187) = 4374
83.
Find the missing term: 10, 100, 200, 310. ?
(A) 400
(B) 410
(C) 420
(D) 430
Solution:
The pattern is + 90, + 100, + 110...... So, the missing term = 310 + 120 = 430
84.
3, 8, 10, 15, 17, 22, 24, ... choose which pair of numbers comes next?
(A) 26, 28
(B) 29, 34
(C) 29, 31
(D) 26, 31
Solution:
This is an alternating addition series that adds 5, then 2, then 5, and so on.
85.
VI, 10, V, 11, __, 12, III. What number should fill the blank?
(A) II
(B) IV
(C) IX
(D) 14
Solution:
This is an alternating addition and subtraction series. Roman numbers alternate with Arabic numbers. In the Roman numeral pattern, each number decreases by 1. In the Arabic numeral pattern, each number increases by 1.
86.
13, 29, 15, 26, 17, 23, 19, ... choose which pair of numbers comes next?
(A) 21, 23
(B) 20, 21
(C) 20, 17
(D) 25, 27
Solution:
Here, there are two alternating patterns, with every other number following a different pattern. The first pattern begins with 13 and adds 2 to each number to arrive at the next; the alternating pattern begins with 29 and subtracts 3 each time.
Let the missing terms of the series be x1 and x2.Thus, the sequence 20, 20, 19, 16, 17, 13, 14, 11. x1, x2 is a combination of two series:I. 20, 19, 17, 14, x1 and II. 20, 16, 13, 11, x2The pattern in I is - 1, - 2, - 3,..............So, missing term, x1= 14 - 4 = 10The pattern in II is - 4, - 3, - 2,.......... So,missing term, x2 = 11 - 1 = 10
88.
Find the missing term: 6, 18, 3, 21, 7, 56, ?
(A) 8
(B) 9
(C) 63
(D) 64
Solution:
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 = 56 or x = 56 ÷ 7 = 8
The given sequence is a combination of two series:I. 13, 24, 35, 46, 57 andII. 32, 43, ?, 65, 76The pattern in both I and II is + 11So, missing term = 43 + 11 = 54
90.
Find the missing term :- 2, 3, 3, 5, 10, 13, ?, 43, 172, 177
(A) 23
(B) 38
(C) 39
(D) 40
Solution:
The pattern is + 1, × 1, + 2, × 2, + 3, × 3, + 4, × 4, + 5 So, missing term = 13 × 3 = 39