## Number Series Questions and Answers Part-11

1. Find the missing term: 2, 12, 36, 80, 150, ?
a) 194
b) 210
c) 252
d) 258

Explanation: The given series is a triangular pattern series.
So, we have
2       12       36       80     150     ?
10       24       44       70
14        20      26
6           6
So, missing term
= 150 + (70 + 26 + 6)
= 150 + 102
= 252

2. Find the missing term: 625, 5, 125, 25, 25, ?, 5
a) 5
b) 25
c) 125
d) 625

Explanation: The given sequence is a combination of two series:
I. 625, 125, 25, 5 and
II. 5, 25, ?
The pattern is ÷ 5, while that in II is × 5.
So, missing term = 25 × 5 = 125

3. Find the missing term: 2, 9, 28, ?, 126, 126, 217, 344
a) 50
b) 65
c) 70
d) 82

Explanation: 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, 30
So, missing term
= 127 + (61 + 24 + 6)
= 127 + 91
= 218

4. Find the missing term: 11, 10, ?, 100, 1001, 1000, 10001
a) 101
b) 110
c) 111
d) None of these

Explanation: The pattern is - 1, × 10 + 1, - 1, × 10 + 1, - 1, × 10 +1, ....
So, the missing term = 10 × 10 + 1 = 101

5. 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

Explanation: The given series consists of cubes of natural numbers only. 256 is not the cube of any natural number.

6. Find out the wrong term: 46080, 3840, 384, 48, 24, 2, 1
a) 384
b) 48
c) 24
d) 2

Explanation: The correct pattern is ÷ 12, ÷ 10, ÷ 8, ÷ 6,.........
So, 24 is wrong and must be replaced by (48 ÷ 6) i.e., 8.

7. Find out the wrong term: 25, 36, 49, 81, 121, 169, 225
a) 36
b) 49
c) 169
d) 225

Explanation: The correct sequence is 52 , 72 , 92 , 112 , 132 , 152.
So, 36 is wrong.

8. Find out the wrong term: 5, 10, 40, 80, 320, 550, 2560
a) 80
b) 320
c) 550
d) 2560

Explanation: The correct pattern is ×2, ×4, ×2, ×4 . . . . . .
So, 550 is wrong and must be replaced by (320 × 2) i.e., 640

9. Find out the wrong term: 2, 5, 10, 17, 26, 37, 50, 64
a) 17
b) 26
c) 37
d) 64