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 5

^{2}, 7

^{2}, 9

^{2}, 11

^{2}, 13

^{2}, 15

^{2}.

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

Explanation: The term of the series are (1

^{2}+ 1)(2

^{2}+ 1)(3

^{2}+ 1)(4

^{2}+ 1)(5

^{2}+ 1)(6

^{2}+ 1)(7

^{2}+ 1),..............

So, 64 is wrong and must be replaced by (8

^{2}+ 1) i.e., 65

10. Find out the wrong term: 3, 7, 15, 39, 63, 127, 255, 511

a) 15

b) 39

c) 63

d) 127

Explanation: The correct pattern is × 2 + 1.

So, 39 is wrong and must be replaced by (15 × 2 + 1) i.e., 31.