**Number Series questions and answers for SSC CHSL:**

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**Instructions:** In each of the following questions. a series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series.

**Question 1:** 325, 259. 204, 160, 127, 105, ?

a) 94

b) 96

c) 98

d) 100

**Question 2:** AZBY, CXDW, EVFU, ?

a) SHTG

b) GXHW

c) GTHS

d) STHO

**Question 3:** 3, 5, 9, 17, ?

a) 42

b) 26

c) 65

d) 33

**Question 4:** 4, 6, 10, 16, 24, ?

a) 40

b) 28

c) 30

d) 34

**Question 5:** 0, 7, 26, 63, ?

a) 123

b) 87

c) 96

d) 124

**Question 6:** 0, ? , 8 27, 64, 125

a) 5

b) 4

c) 2

d) 1

**Question 7:** 1, 5, 25, 125, ? , ? , ?

a) 245, 485, 965

b) 225, 325, 425

c) 625.3225, 15605

d) 625, 3125, 15625

**Question 8:** 2, 2, 4, 6, ?, 10, 8, 14, 10

a) 6

b) 5

c) 8

d) 7

**Question 9:** 3, 11, 38, 102, 227,?

a) 245

b) 487

c) 474

d) 443

**Question 10:** 3,15, 8, 24, 15, 35, ? , 48, 35

a) 24

b) 46

c) 26

d) 25

**Solutions for Number Series for SSC CHSL:**

**Solutions: **

**1) Answer (A)**

here the given pattern is 325, 259. 204, 160, 127, 105, ?

and so let the missing number be y

here we can see that

259 – 325 = -66

204 – 259 = -55

160 – 204 = -44

127 – 160 = -33

105 – 127 = -22

here we can see that every time the difference is reducing by -11

so , y – 105 = -11

y = 94

**2) Answer (C)
**AZBY:

A is the first letter in the alphabetical series. It is followed by the first letter from the last, Z.

B is the second letter in the alphabetical series. It is followed by the second last letter, Y.

The next term starts with ‘C’, the letter following B.

CXDW:

C is the third letter from the start and X is the third letter from the end.

D is the fourth letter from the start and W is the fourth letter from the end.

The next term starts with ‘E’, the letter following D.

EVFU:

E is the fifth letter from the start and V is the fifth letter from the end.

F is the sixth letter from the start and U is the sixth letter from the end.

Logically, the next term must start with ‘G’.

G is the seventh letter from the start. The seventh letter from the end is T.

H is the eighth letter from the start. The eighth letter from the end is S.

Therefore, the next term must be GTHS. Hence, option C is the right answer.

**3) Answer (D)
**here the given pattern is 3, 5, 9, 17, ?

let the missing term be y

we can see that

5 – 3 = 2^1

9 -5 = 4 = 2^2

17 – 9 = 8 = 2^3

as we can see that every time the difference between consecutive terms is getting increased by power of 2 and hence , y – 17 = 2^4 = 16

y = 33

**4) Answer (D)
**here the given pattern is 4, 6, 10, 16, 24, ?

let the missing term be y

6 – 4 = 2

10 – 6 = 4

16 – 10 = 6

24 – 16 = 8

as we can see that every time the difference is getting increased by 2 so

y – 24 = 10

y = 34

**5) Answer (D)
**let the missing term be y

here the given series is 0, 7, 26, 63, y

as we can see that :

0 = 0^2 -1

7 = 2^3 – 1

26 = 3^3 – 1

63 = 4^3 – 1

as we can see that all number are equal to cub of consecutive whole numbers minus 1 and hence , y = 5^3 – 1= 124

**6) Answer (D)
**here the given pattern is 0, ? , 8 27, 64, 125

let the missing term be y

as we can see that every patern is a cube of consecutive whole number starting from 0

0 = 0^3

8 = 2^3

64 = 4^3

125 = 5^3

so the missing term is , y = 1 ^ 3 = 1

**7) Answer (D)
**we have been give a series as 1, 5, 25, 125, ? , ? , ?

here we can see that every term is a power of 5

1 = 5 ^ 0

5 = 5 ^ 1

25 = 5 ^ 2

125 = 5 ^ 3

so the next term will also be power of 5 and the terms are 5 ^ 4, 5 ^ 5 , 5^6 i,e 625, 3125, 15625

**8) Answer (A)
**here the given pattern is 2, 2, 4, 6, ?, 10, 8, 14, 10

let the missing term be y

here 2 series are present

1st series : 2, 4, y, 8, 10

2nd series: 2, 6, 10, 14

as we can see that the missing term is a part of 1st series

and in 1st series difference between consecutive terms is 2

so 4-2 = y-4

y = 6

**9) Answer (D)
**here the given series is 3, 11, 38, 102, 227,?

let the missing term be y

we can see that

11 – 3 = 8 = 2^3

38 – 11 = 27 = 3^3

102 – 38 = 64 = 4^3

227 – 102 = 125 = 5^3

hence y – 227 = 6^3 = 216

y = 216 + 227 = 443

**10) Answer (A)
**the given pattern is 3,15, 8, 24, 15, 35, ? , 48, 35

let the missing term be y

here we can see that 2 series are running

1st series : 3 , 8 , 15 , y , 35

2nd series : 15, 24 , 35 , 48

as the missing term is a part of 1st pattern then

8 – 3 = 5

15 – 8 = 7

as the difference is increasing by 2 every time and hence

y – 15 = 9

y = 24