## Question

`Find the wrong number in the series.`

` 1, 2, 6, 15, 31, 56, 91`

`Find the wrong number in the series.`

` 1, 2, 6, 15, 31, 56, 91`

A. 91

B. 31

C. 15

D. 56

**Answer: A. 91**

**Solution:**

The difference between the two consecutive numbers is 1, 4, 9, 16, 25, 35. (2-1, 6-2, 15-6, 31-15, …)

This is clearly , +(1^{2}), +(2^{2}), +(3^{2}), +(4^{2}), +(5^{2}),+(6^{2})

Here 35 is wrong, So our wrong number is **91**.

**Read more:**

**Find the missing number in the series? 4, 18, ?, 100, 180, 294, 448**

**Find the missing number in the series? 3, 7, 24, 11, ___, 19, 19, …..**