WBCS.LIVE practice question

Which number will replace the question mark(?) in the following series? 17, 37, 77, 157, 317, ?

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. 683
  2. 637
  3. 649
  4. 634

Correct answer and explanation

Correct answer: 637

Explanation: āœ… Correct Answer: B) 637 šŸ“š Explanation: The series increases by multiplying the previous number by 2 and then subtracting a specific value, or by adding expanding gaps: $+20, +40, +80, +160$. The differences double with each step. The next difference to add is $160 \times 2 = 320$. Calculating $317 + 320$ results in exactly 637 as the next number in the sequence.