Question

In each of the following number series, the wrong number is given, find out that number.

1, 5, 20, 57, 121, 221, 365

1. 57
2. 20
3. 121
4. 5
5. 365

Answer 1

Correct Answer - Option 2 : 20

Given:

The given number series is:

1, 5, 20, 57, 121, 221, 365

Concept Used:

A number series, with the relation between successive terms.

Calculation:

The given number series follows the relation:

1 + 2² = 5,

5 + 4² = 21,

21 + 6² = 57,

57 + 8² = 121, 

121 + 10² = 221,

221 + 12² = 365

∴ The wrong number in the given series is 20