1.  In each of the following questions, one term in the number series is wrong. Find out the wrong term.
89, 78, 86, 80, 85, 82, 83
A. 83
B. 82
C. 86
D. 78

Answer: Option C

Explanation:

The correct pattern is - 11, + 9, - 7, + 5, - 3, + 1. So, 86 is wrong and must be replaced by ( 78+ 9 ) i. e. 87.