Find out the incorrect number 1, 5, 5, 9, 7, 11, 11, 15, 12, 17 - Number Series - Series Completio

In following questions, one term in number series is incorrect. - Find out the incorrect number 1, 5, 5, 9, 7, 11, 11, 15, 12, 17

A. 11

B. 12

C. 17

D. 15

E. None of the above

Answer: B. 12

The given sequence is a combination of two series :
I. 1, 5, 7, 11, 12 and
II. 5, 9, 11, 15, 17
The pattern in both I and II is + 4, + 2, + 4, + 2.
So, 12 is wrong and must be replaced by (11 + 2) i.e. 13.

Posted in: Number Series - Series Completion - Verbal Reasoning