1st term : 4 2nd term : 4 + 2 = 6 3rd term : 6 + 4 = 10 4th term : 10 + 6 = 16 5th term : 16 + 8 = 24 So, 6th term : 24 + 10 = 34
13.
Find the missing term: 2, 3, 5, 7, 11, ?, 17
(A) 12
(B) 13
(C) 14
(D) 15
Solution:
Clearly, the given series consists of prime numbers starting from 2. So, the missing term is the prime number after 11, which is 13.
14.
Find out the wrong term: 1, 5, 9, 15, 25, 37, 49
(A) 9
(B) 15
(C) 25
(D) 37
Solution:
The terms of the given series are 12 , (22 + 1), 32 , (42 + 1), 52 , (62 + 1), 72 So, 15 is wrong and must be replaced by (42 + 1) i.e., 17.
15.
14, 28, 20, 40, 32, 64, ... What number should come next?
(A) 52
(B) 56
(C) 96
(D) 128
Solution:
This is an alternating multiplication and subtracting series: First, multiply by 2 and then subtract 8.
16.
What will come at the place of question mark ? 10, 100, 200, 310, ?
(A) 430
(B) 420
(C) 410
(D) 400
Solution:
1st term : 10 2nd term : 100 = 10+90 3rd term : 200 = 100+100 4th term : 310 = 200+110 5th Term: 430 = 310+120 Therefore, the answer is 430.
17.
8, 22, 8, 28, 8, ... What number should come next?
(A) 9
(B) 29
(C) 32
(D) 34
Solution:
This is a simple addition series with a random number, 8, interpolated as every other number. In the series, 6 is added to each number except 8, to arrive at the next number.
18.
Find the missing number: 3, 7, 15 ,?, 63 ,127
(A) 30
(B) 31
(C) 47
(D) 52
Solution:
Each number in the series is one more than twice the preceding number.So, the missing term = (15 x 2) + 1 = 31
19.
4, 7, 25, 10, __, 20, 16, 19. What number should fill the blank?
(A) 13
(B) 15
(C) 20
(D) 28
Solution:
Two series alternate here, with every third number following a different pattern. In the main series, 3 is added to each number to arrive at the next. In the alternating series, 5 is subtracted from each number to arrive at the next.
20.
Find out the wrong term: 10, 26, 74, 218, 654, 1946, 5834
(A) 26
(B) 74
(C) 218
(D) 654
Solution:
The correct pattern is × 3, - 4,............ So, 654 is wrong and must be replaced by (218 × 3 - 4) i.e., 650.