1. 20, 20, 17, 17, 14, 14, 11, ... choose which pair of numbers comes next?

a) 8, 8

b) 11, 11

c) 11, 14

d) 11, 8

Explanation: This is a simple subtraction with repetition series. It begins with 20, which is repeated, then 3 is subtracted, resulting in 17, which is repeated, and so on.

2. 61, 57, 50, 61, 43, 36, 61, ... choose which pair of numbers comes next?

a) 29, 61

b) 27, 20

c) 31, 61

d) 29, 22

Explanation: This is an alternating repetition series, in which a random number, 61, is interpolated as every third number into an otherwise simple subtraction series. Starting with the second number, 57, each number (except 61) is 7 less than the previous number.

3. 9, 12, 11, 14, 13, 16, 15, ... choose which pair of numbers comes next?

a) 14, 13

b) 18, 21

c) 14, 17

d) 18, 17

Explanation: This is a simple alternating addition and subtraction series. First, 3 is added, then 1 is subtracted, then 3 is added, 1 subtracted, and so on.

4. 4, 8, 22, 12, 16, 22, 20, 24, ... choose which pair of numbers comes next?

a) 28, 32

b) 28, 22

c) 22, 28

d) 32, 36

Explanation: This is an alternating repetition series, with a random number, 22, interpolated as every third number into an otherwise simple addition series. In the addition series, 4 is added to each number to arrive at the next number.

5. 40, 40, 31, 31, 22, 22, 13, ... choose which pair of numbers comes next?

a) 13, 4

b) 13, 5

c) 4, 13

d) 9, 4

Explanation: This is a subtraction series with repetition. Each number repeats itself and then decreases by 9.

6. What will come at the place of question mark ?

2, 3, 6, 15, ?, 123

a) 47

b) 42

c) 45

d) 50

Explanation:

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

7. In the following number series a wrong number is given. Find out the wrong number.

1, 3, 10, 21, 64, 129, 356, 777

a) 129

b) 21

c) 10

d) 356

Explanation:

The given pattern is,

2^{nd} term → 1*2+1 = 3

3^{rd} term → 3*3+1 = 10

4^{th} term → 10*2+1 = 21

5^{th} term → 21*3+1 = 64

6^{th} term → 64*2+1 = 129

7^{th} term → 129*3+1= 388

So, 7^{th} term **356** is wrong and must be replaced by **388**.

8. What will come at the place of question mark ?

9, 27, 31, 155, 161, 1127, ?

a) 316

b) 1135

c) 1288

d) 2254

Explanation:

Given pattern is,

2^{nd} term → **9*3** = 27

3^{rd} term → **27+4** = 31

4^{th} term → **31*5 ** = 155

5^{th} term → **155+6** = 161.

6^{th} term → **161*7** = 1127

Missing term → **1127+8** = 1135.

9. What will come at the place of question mark ?

2, 7, 27, 107, 427, ?

a) 1262

b) 1707

c) 4027

d) 4207

Explanation:

The pattern is,

2^{nd} term → **2 +(5 *1 ^{2})** = 7

3

^{rd}term →

**7 +(5 *2**= 27

^{2})4

^{th}term →

**27 +(5 *4**= 107

^{2})5

^{th}term →

**107 +(5 *8**= 427

^{2})Missing term →

**427 +(5 *16**= 1707

^{2})10. Sunday, Monday, Wednesday, Saturday, Wednesday, Monday, ...

a) Sunday, Sunday

b) Sunday, Monday

c) Sunday, Wednesday

d) Sunday, Saturday

Explanation:

Sunday to Monday = no gap

Monday to Wednesday = One day gap.

Wednesday to Saturday = Two days gap.

Saturday to Wednesday = Three days gap.

Wednesday to Monday = Four days gap.

In the next term there must be five days and six days gap.

So, Next term would be Sunday, Sunday.