Multiple choice general knowledge math & puzzles

Look at this series: 4, 7, 25, 10, __, 20, 16, 19, ... What number should fill the blank?

  1. 13

  2. 15

  3. 20

  4. 28
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This series has two interleaved patterns: (1) 4, 25, __, 20, 16 adds 3, subtracts 2, adds 3, subtracts 4; (2) 7, 10, 19 subtracts 3 each time. Filling the blank in pattern 1: 25 - 2 = 13. The series is: 4 (+3) 7, 25 (-2) 23 (not shown), 10 (+3) 13, 20, etc. Option A (13) fits.

Keep practicing — related questions