Correct Answer - Option 4 : 20
Given:
24, 31, 17, 38, 20, 45
Calculation:
The series follows the following pattern,
24 + 7 = 31
31 - 14 = 17
17 + 21 = 38
38 - 28 = 10 ≠ 20
10 + 35 = 45
Since 10 will come in place of 20.
∴ The required wrong number will be 20.