What should come in place of the question mark (?) in the following series?
3, 7, 15, 31, 63, ?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 127.
Given series: 3, 7, 15, 31, 63, ?
3 × 2 + 1 = 7,
7 × 2 + 1 = 15,
15 × 2 + 1 = 31,
31 × 2 + 1 = 63,
63 × 2 + 1 = 127