WBCS.LIVE practice question

Complete the following series: 9, 11, 15, 23, 39, ?

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

Answer options

  1. 71
  2. 64
  3. 42
  4. 56

Correct answer and explanation

Correct answer: 71

Explanation: āœ… Correct Answer: A. 71 šŸ“š Explanation: The sequence follows a pattern of adding powers of 2 (multiplied by 2): +2, +4, +8, +16. The next number will be 39 + 32 = 71. Each step adds double the amount of the previous step. Identifying this geometric progression in differences is the key to completing the series.