Question 1

2,3,8,27, 112,?

Accepted Answer

The pattern is x 1 + 1, x 2 + 2, x 3 + 3, x 4 + 4,..... So, missing term = 112 x 5 + 5 = 565.

Question 2

6, 17, 39, 72,?

Accepted Answer

The pattern is + 11, + 22, + 33, ..... So, missing term = 72 + 44 = 116.

Question 3

20, 20, 19, 16, 17, 13, 14, 11,?,?

Accepted Answer

Let the missing terms of the series be x1 and x2. Thus, the sequence 20, 20, 19, 16, 17, 13, 14, 11, xv x2 is a combination of two series : I. 20, 19, 17, 14, x1 and II. 20, 16, 13, 11, x2 The pattern in I is - 1, - 2, - 3,......So, missing term, x1 = 14 - 4 = 10. The pattern in II is - 4, - 3, - 2,......So, missing term, x2 = 11 - 1 = 10.

Question 4

24, 60, 120, 210,?

Accepted Answer

The pattern is + 36, + 60, + 90,.....i.e. + [6 x (6 + 0)], + [6 x (6 + 4)], + [6 x (6 + 9)],... So, missing term = 210 + [6 x (6 + 15)] = 210 + 126 = 336.

Question 5

625, 5, 125, 25, 25,?, 5

Accepted Answer

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

Question 6

10, 100, 200, 310,?

Accepted Answer

The pattern is + 90 + 100, + 110,..... So, missing term = 310 + 120 = 430.

Question 7

11, 10,?, 100, 1001, 1000, 10001

Accepted Answer

The pattern is - 1, x 10 + 1, - 1, x 10 + 1, - 1, x 10 + 1, ..... So, missing term = 10 x 10 + 1 = 101.

Question 8

2, 7, 27, 107, 427,?

Accepted Answer

The pattern is + 5, + 20, + 80, + 320, ...... i.e. + (5 x 12), + (5 x 22), + (5 x 42), + (5 x 82),..... So, missing term = 427 + (5 x 162) = 427 + 1280 = 1707.

Question 9

1, 1, 2, 6, 24,?, 720

Accepted Answer

The pattern is x 1, x 2, x 3, x 4,..... So, missing term = 24 x 5 = 120.

Question 10

2, 15, 4, 12, 6, 7,?,?

Accepted Answer

Let the missing terms of the series be x1 and x2. Thus, the sequence 2, 15, 4, 12, 6, 7, x1 x2 is a combination of two series : I. 2, 4, 6, x1 and II. 15, 12, 7, x2I consists of consecutive even numbers. So, missing term, x1 = 8. The pattern in II is - 3, - 5,......So, missing term, x2 = 7 - 7 = 0.

Question 11

4832, 5840, 6848,?

Accepted Answer

The pattern is + 1008. So, missing term - 6848 + 1008 = 7856.

Question 12

5824, 5242,?, 4247, 3823

Accepted Answer

Each term in the series is obtained by subtracting from the preceding term the number formed by the first three digits of the preceding term. So, missing term = 5242 - 524 = 4718.

Question 13

2, 8, 16, 128,?

Accepted Answer

Each term in the series, except the first two terms, is the product of the preceding two terms. So, missing term = 16 x 128 = 2048.

Question 14

1, 2, 6, 7, 21, 22, 66, 67,?

Accepted Answer

The pattern is + 1, x 3, + 1, x 3, + 1, x 3, + 1,..... So, missing term = 67 x 3 = 201.

Question 15

0.5, 0.55, 0.65,0.8,?

Accepted Answer

The pattern is + 0.05, + 0.10, + 0.15,..... So, missing term = 0.8 + 0.20 = 1.

Question 16

0, 2, 3, 5, 8, 10, 15, 17, 24, 26,?

Accepted Answer

The given sequence is a combination of two series : I. 0, 3, 8, 15, 24, ? and II. 2, 5, 10, 17, 26 The pattern in each one of I and II is + 3, + 5, + 7, + 9, ..... So, missing term = 24 + 11 = 35.

Question 17

11, 13, 17, 19, 23, 25,?

Accepted Answer

The pattern is + 2, + 4, + 2, + 4, ..... So, missing term = 25 + 4 = 29.

Question 18

5, 2, 7, 9, 16, 25,?

Accepted Answer

Each term in the series, except the first two terms, is the sum of the preceding two terms. So, missing term = 16 + 25 = 41.

Question 19

7, 26, 63, 124, 215, 342,?

Accepted Answer

The terms of the given series are (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1),..... So, missing term = (83 - 1) = (512 - 1) = 511.

Question 20

3, 12,27,48, 75, 108,?

Accepted Answer

The terms of the given series are 3 x l2, 3 x 22, 3 x 32, 3 x 42, 3 x 52, 3 x 62,..... So, missing term = 3 x 72 = 3 x 49 = 147.

Series Completion Questions