Question 1

5, 10, 40, 80, 320, 550, 2560

Accepted Answer

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

Question 2

2, 3, 4, 4, 6, 8, 9, 12, 16

Accepted Answer

The given sequence is a combination of three series: I. 1st, 4th, 7th terms i.e. 2, 4, 9,..... II. 2nd, 5th, 8th terms i.e. 3, 6, 12,..... III. 3rd, 6th, 9th terms i.e. 4, 8, 16,..... In each one of I, II and III, each term is twice the preceding term. So, 9 is wrong and must be replaced by (4 x 2) i.e. 8.

Question 3

11, 5, 20, 12, 40, 26, 74, 54

Accepted Answer

The given sequence is a combination of two series : I. 11, 20, 40, 74 and II. 5, 12, 26, 54 The correct pattern in I is + 9, + 18, + 36,..... So, 40 is wrong and must be replaced by (20 + 18) i.e. 38.

Question 4

5, 27, 61, 122, 213, 340, 509

Accepted Answer

The terms of the series are (23 - 3), (33 - 3), (43 - 3), (53 - 3), (63 - 3), (73 - 3), (83-3). So, 27 is wrong and must be replaced (33 - 3) i.e. 24.

Question 5

3, 7, 15, 39, 63, 127, 255, 511

Accepted Answer

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

Question 6

380, 188, 92, 48, 20, 8, 2

Accepted Answer

The correct pattern is - 192, - 96, - 48, - 24, - 12, - 6. So, 48 is wrong and must be replaced by (92 - 48) i.e. 44.

Question 7

16, 22, 30, 45, 52, 66

Accepted Answer

The correct pattern is + 6, + 8, + 10, + 12, + 14. So, 45 is wrong and must be replaced by (30 + 10) i.e. 40.

Question 8

10, 26, 74, 218, 654, 1946, 5834

Accepted Answer

The correct pattern is x 3 - 4. So, 654 is wrong and must be replaced by (218 x 3 - 4) i.e. 650.

Question 9

24576, 6144, 1536, 386, 96, 24

Accepted Answer

Each term of the series is obtained by dividing the preceding term by 4. So, 1536 is wrong and must be replaced by (1536 + 4) i.e. 384.

Question 10

10, 14, 28, 32, 64, 68, 132

Accepted Answer

The correct pattern is + 4, x 2, + 4, x 2, ..... So, 132 is wrong and must be replaced by (68 x 2) i.e. 136.

Question 11

46080, 3840, 384, 48, 24, 2, 1

Accepted Answer

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

Question 12

89, 78, 86, 80, 85, 82, 83

Accepted Answer

The correct pattern is - 11, + 9, - 7, + 5, - 3, + 1. So, 86 is wrong and must be replaced by (78 + 9) i.e. 87.

Question 13

0, 2, 3, 5, 8, 10, 15, 18, 24, 26, 35

Accepted Answer

The given sequence is a combination of two series: I. 0, 3, 8, 15, 24, 35 and II. 2, 5, 10, 18, 26 The pattern in both I and II is + 3, + 5, + 7, + 9,..... So, in II, 18 is wrong and must be replaced by (10 + 7) i.e. 17.

Question 14

325, 259, 202, 160, 127, 105, 94

Accepted Answer

The correct pattern is - 66, - 55, - 44, - 33, - 22, - 11. So, 202 is wrong and must be replaced by (259 - 55) i.e. 204.

Question 15

1236, 2346, 3456, 4566, 5686

Accepted Answer

The correct pattern in the series is + 1110. So, 5686 is wrong and must be replaced by (4566 + 1110) i.e. 5676.

Question 16

93, 309, 434, 498, 521, 533

Accepted Answer

The correct pattern is + 63, + 53, + 43, + 33, ..... So, 521 is wrong and must be replaced by (498 + 33) i.e. 525.

Question 17

WFB, TGD, QHG,?

Accepted Answer

Question 18

AZ, GT, MN,?, YB

Accepted Answer

Question 19

H, I, K, N,?

Accepted Answer

Question 20

Z, S, W, O, T, K, Q, G,?,?

Accepted Answer

The given sequence is a combination of two series: I. Z, W, T, Q, ? and II. S, O, k, G, ?

Series Completion Questions