Which of the following numbers will replace the question mark (?) in the given series?
4, 9, 17, 35, ?, 139
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 69.
Given series: 4, 9, 17, 35, ?, 139
The series follows this pattern:
4 × 2 + 1 = 8 + 1 = 9
9 × 2 - 1 = 18 - 1 = 17
17 × 2 + 1 = 34 + 1 = 35
35 × 2 - 1 = 70 - 1 = 69
69 × 2 + 1 = 138 + 1 = 139
So, the missing term in the series is 69.