What should come in place of the question mark (?) in the given series?
9, 17, 33, 65, 129, ?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 257.
Given series: 9, 17, 33, 65, 129, ?
9 × 2 - 1 = 17, 17 × 2 - 1 = 33, 33 × 2 - 1 = 65, 65 × 2 - 1 = 129, 129 × 2 - 1 = 257