series completion verbal reasoning questions

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Directions to Solve

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

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.