Question - Find the wrong number in the series.
1, 2, 6, 15, 31, 56, 91
A) 31 B) 15
C) 56 D) 91
Answer -
D) 91
Explanation:
The difference of the two consecutive numbers are 1, 4, 9, 16, 25, 35.
This is clearly , +(12), +(22), +(32), +(42), +(52),+(62)
Here 35 is wrong, So our wrong number is 91