series completion verbal reasoning questions

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

11.

3, 4, 7, 7, 13, 13, 21, 22, 31, 34, ?
A.     42    B.     43
C.     51    D.     52
Answer & Explanation

Answer: Option B

Explanation:

The given sequence is a combination of two series :

I. 3, 7, 13, 21, 31, ? and II. 4, 7, 13, 22, 34

The pattern in I is + 4, + 6, + 8, + 10,…..

The pattern in II is + 3, + 6, + 9, + 12,…..

So, missing term = 31 + 12 = 43.

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12.

198, 194, 185, 169, ?
A.     92    B.     112
C.     136    D.     144
Answer & Explanation

Answer: Option D

Explanation:

The pattern is – 4, – 9, – 16,…..i.e. – 22, – 32, – 42,…..

So, missing pattern = 169 – 52 = 169 – 25 = 144.

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13.

2, 3, 5,7,11,?, 17
A.     12    B.     13
C.     14    D.     15
Answer & Explanation

Answer: Option B

Explanation:

Clearly, the given series consists of prime numbers starting from 2. So, the missing

term is the prime number after 11, which is 13.

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14.

6, 12, 21, ?, 48
A.     33    B.     38
C.     40    D.     45
Answer & Explanation

Answer: Option A

Explanation:

The pattern is + 6, + 9, + 12, + 15, …..

So, missing term = 21 + 12 = 33.

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15.

Which term of the series 5, 10, 20, 40, ….. is 1280?
A.     10th
B.     9th
C.     8th
D.     None of these
Answer & Explanation

Answer: Option B

Explanation:

Clearly, 5 x 2 = 10, 10 x 2 = 20, 20 x 2 = 40,…..

So, the series is a G.P. in which a = 5 and r = 2.

Let 1280 be the rath term of the series.

Then, 5x2n-1 = 1280 2n-1 = 256 = 28 n – 1 = 8 n = 9.