Multiple choice general knowledge math & puzzles

Identify the missing number in the series…9, ? , 15, 21, 29, 39….

  1. 13

  2. 12

  3. 10

  4. 11
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D Correct answer
Explanation

The pattern adds consecutive prime numbers: 9+2=11, 11+4=15, 15+6=21, 21+8=29, 29+10=39. The differences are 2, 4, 6, 8, 10 - consecutive even numbers. The missing number is 11.

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