Which of the following numbers will replace the question mark (?) in the given series?
1, 6, 31, 156,? , 3906
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 781.
1 × 5 + 1 = 6,
6 × 5 + 1 = 31,
31 × 5 + 1 = 156,
156 × 5 + 1 = 781,
781 × 5 + 1 = 3906
Hence, the correct answer is 781.