Find out the incorrect number 3, 7, 15, 39, 63, 127, 255, 511 - Number Series - Series Completion

In following questions, one term in number series is incorrect. - Find out the incorrect number 3, 7, 15, 39, 63, 127, 255, 511

A. 15

B. 39

C. 63

D. 127

E. None of the above

Answer: B. 39

Each number in the series is multiplied by 2 and the result increased by 1 to obtain the next number.
So, 39 is wrong and should be replaced bu (15 * 2 + 1) i.e. 31.

Posted in: Number Series - Series Completion - Verbal Reasoning