Series Completion - Section 2

 

Series Completion - Section 2

Choose the correct alternative that will continue the same pattern and replace the question mark in the given series.

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

A.100

B.104

C.108

D.120

Answer: Option-D

Explanation:

The pattern is x 1, x 2, x 3, x 4,…..

So, missing term = 24 x 5 = 120.

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

A.8, 8

B.8, 0

C.3, 8

D.None of these

Answer: Option-B

Explanation:

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.

3. 4832, 5840, 6848, ?

A.7815

B.7846

C.7856

D.7887

Answer: Option-C

Explanation:The pattern is + 1008.

So, missing term - 6848 + 1008 = 7856.

4. 5824, 5242, ?, 4247, 3823

A.4467

B.4718

C.4856

D.5164

Answer: Option-B

Explanation: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.

5. 2, 8, 16, 128, ?

A.2042

B.2046

C.2048

D.2056

Answer: Option-C

Explanation: 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.

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

A.70

B.134

C.201

D.301

Answer: Option-C

Explanation:

The pattern is + 1, x 3, + 1, x 3, + 1, x 3, + 1,.....

So, missing term = 67 x 3 = 201.

7. 0.5, 0.55, 0.65,0.8,?

A.0.9

B.0.82

C.1

B.0.95

Answer: Option-C

Explanation:

The pattern is + 0.05, + 0.10, + 0.15,.....

So, missing term = 0.8 + 0.20 = 1.

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

A.28

B.30

C.32

D.35

Answer: Option-D

Explanation: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.

9. 11, 13, 17, 19, 23, 25, ?

A.26

B.27

C.29

D.37

Answer: Option-C

Explanation: The pattern is + 2, + 4, + 2, + 4, …..

So, missing term = 25 + 4 = 29.

10. 5, 2, 7, 9, 16, 25, ?

A.41

B.45

C.48

D.52

Answer: Option-A

Explanation:Each term in the series, except the first two terms, is the sum of the preceding two

terms.

So, missing term = 16 + 25 = 41.

11. 7, 26, 63, 124, 215, 342, ?

A.391

B.421

C.481

D.511

Answer: Option-D

Explanation: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.

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

A.147

B.162

C.183

D.192

Answer: Option-A

Explanation: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.

13. 3, 7, 23, 95, ?

A.62

B.128

C.479

D.575

Answer: Option-C

Explanation:The pattern is x 2 + 1, x 3 + 2, x 4 + 3,.....

So, missing term = 95 x 5 + 4 = 479.

14. 6, 18, 3, 21, 7, 56, ?

A.8

B.9

C.63

D.64

Answer: Option-A

Explanation: Each term at an even place in the series is the product of its two adjacent terms.

Thus, if the missing term be x, then we have : 7 x x = 56 or x = 56 ÷ 7 = 8.

15. 4, 9, 25, ?, 121, 169, 289, 361

A.49

B.64

C.81

D.87

Answer: Option-A

Explanation: The given series consists of squares of consecutive prime numbers

i.e. 2², 3², 5²,.....,

11², 13², 17², 19².

So, missing term = 7² = 49.

16. 6, 13,28,59,?

A.111

B.113

C.114

D.122

Answer: Option-D

Explanation:

The pattern is x 2 + 1, x 2 + 2, x 2 + 3,.....

So, missing term = 59 x 2 + 4 = 122.

17. 4, 12, 36, 108, ?

A.144

B.216

C.304

D.324

Answer: Option-D

Explanation:

The pattern is x 3.

So, missing term = 108 x 3 = 324.

18. Which term of the series 5, 8, 11, 14,.....is 320 ?

A.104th

B.105th

C.106th

D.64th

Answer: Option-C

Explanation: Clearly, 5 + 3 = 8, 8 + 3 = 11, 11 + 3 = 14, .....

So, the series is an A.P. in which a - 5 and d = 3.

Let 320 be the nth term of the series.

Then, 320 = 5 + (n - 1) x 3 or (n - 1) = 105 or n = 106.

19. 8, 9, 8, 7, 10, 9, 6, 11, 10, ?, 12

A.5

B.7

C.8

D.11

Answer: Option-A

Explanation:

The given sequence is a combination of three series :

I. 1st, 4th, 7th, 10th terms i.e. 8, 7, 6, ?

II. 2nd, 5th, 8th, 11th terms i.e. 9, 10, 11, 12

III. 3rd, 6th, 9th terms i.e. 8, 9, 10 The pattern in I is - 1.

So, missing term = 6 - 1 = 5.

20. 3, 7, 15, ?, 63, 127

A.30

B.31

C.47

D.52

Answer: Option-B

Explanation:

Each number in the series is one more than twice the preceding number.

So, missing term = (15 x 2) + 1 = 31.

21. 4, 10, ?, 82, 244, 730

A.24

B.28

C.77

D.218

Answer: Option-B

Explanation: Each number in the series is 2 less than thrice the preceding number.

So, missing number = (10 x 3) - 2 = 28.

22. 1, 5, 13,25,41,?

A.51

B.57

C.61

D.63

Answer: Option-C

Explanation:The pattern is + 4, + 8, + 12, + 16......

So, missing term = 41 + 20 = 61.

23. 325, 259, 204, 160, 127, 105, ?

A.94

B.96

C.98

D.100

Answer: Option-A

Explanation:

The pattern is - 66, - 55, - 44, - 33, - 22, .....

So, missing term = 105 - 11 = 94.

24. 4, 7, 12, 19, 28, ?

A.30

B.36

C.39

D.49

Answer: Option-C

Explanation:

The pattern is + 3, + 5, + 7, + 9, .....

So, missing term = 28 + 11 = 39.

25. 5760, 960, ?, 48, 16, 8

A.120

B.160

C.192

D.240

Answer: Option-C

Explanation:The pattern is ÷ 6, ÷ 5, ÷ 4, ÷ 3, ÷ 2.

So, missing term = 960 - 5 = 192.

26. 45, 54, 47, ?, 49, 56, 51, 57, 53

A.48

B.50

C55

D.None of these

Answer: Option-C

Explanation:The given sequence is a combination of two series:

I. 45, 47, 49, 51, 53 and II. 54, ?, 56, 57

Clearly, II consists of consecutive natural numbers, starting from 54.

So, missing term = 55.

27. 3, 8, 13, 24, 41, ?

A.70

B.75

C.80

D.85

Answer: Option-A

Explanation:The pattern followed is : nth term + (n + l)th term + (n + 1) = (n + 2)th term.

Thus, 1st term + 2nd term + 2 = 3rd term; 2nd term + 3rd term + 3 = 4th term and so on.

So, missing term = 6th term = 4th term + 5th term + 5 = 24 + 41 + 5 = 70.

28. 10, 14, 26, 42, 70, ?

A.100

B.102

C.106

D.114

Answer: Option-D

Explanation:Each term in the series, except the first two terms, is 2 more than the sum of the preceding two terms.

So, missing term = (42 + 70) + 2 = 114.

29. 10, 18, 28, 40, 54, 70, ?

A.85

B.86

C.87

D.88

Answer: Option-D

Explanation:The pattern is + 8, + 10, + 12, + 14, .....

So, missing term = 70 + 18 = 88.

30. 8, 28, 116, 584, ?

A.1752

B.3502

C.3504

D.3508

Answer: Option-D

Explanation:The pattern is x 3 + 4, x 4 + 4, x 5 + 4,.....

So, missing term = 584 x 6 + 4 = 3508.