Question

In following questions, one term in number series is incorrect.
Find out the incorrect number 1, 3, 7, 15, 27, 63, 127.

• A. 7
• B. 15
• C. 27
• D. 63

Answer 1

Answer: (C)

27

The sequence is $+2,+4,+8,....i.e.+2,+2^2,+2^3,....$
So, 27 is wrong and must be replaced by (15 + 24) i.e. (15 +16) or 31.