In this type of questions, one term in the number series is wrong. Find out the wrong term.

121, 143, 165, 186, 209

Answer: Option C

Explanation:

Each term in the series is obtained by adding 22 to the preceding term.

So, 186 is wrong and must be replaced by (165 + 22) i.e. 187.

6, 15, 35, 77, 165, 221

The terms of the series are products of two consecutive prime numbers i.e. (2 x 3),

(3 x 5), (5 x 7), (7 x 11),.....

So, 165 is wrong and must be replaced by (11 x 13) i.e. 143.

8, 13, 21, 32, 47, 63, 83

Answer: Option D

The correct pattern is + 5, + 8, + 11, + 14,.....

So, 47 is wrong and must be replaced by (32 + 14) i.e. 46.

1, 2, 4, 8, 16, 32, 64, 96

Each term of the series is obtained by multiplying the preceding term by 2.

So, 96 is wrong and must be replaced by (64 x 2) i.e. 128.

3, 4, 10, 32, 136, 685, 4116

Answer: Option B

The correct pattern is x 1 + 1, x 2 + 2, x 3 + 3, x 4 + 4,.....

So, 32 is wrong and must be replaced by (10 x 3 + 3) i.e. 33.