Multiple choice general knowledge math & puzzles

6, 9, 15, 21, 24, 28, 30

  1. 28

  2. 24

  3. 21

  4. 30
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In 6, 9, 15, 21, 24, 28, 30, all numbers are multiples of 3 except 28. Check: 6÷3=2, 9÷3=3, 15÷3=5, 21÷3=7, 24÷3=8, 30÷3=10, but 28÷3≈9.33 (not an integer). 28 is the only non-multiple of 3.

AI explanation

Every number besides 28 is a multiple of 3 (6, 9, 15, 21, 24, 30), so 28 is the one that doesn't fit since 28 isn't divisible by 3. The trick is identifying the shared factor common to the rest of the set.

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