Multiple choice general knowledge math & puzzles

There is a number that is 3 times the sum of its digits. What is this number?

  1. 24

  2. 27

  3. 36

  4. 42
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the number be 10a + b, where a and b are its digits. The condition is 10a + b = 3(a + b), which simplifies to 7a = 2b. Since a and b are digits from 0-9, the only integer solution is a = 2, b = 7. Checking: 27 = 3 × (2 + 7) = 3 × 9 = 27, which satisfies the condition.

AI explanation

Checking 27: its digits sum to 2+7=9, and 3×9=27, exactly matching the number itself. This is the defining property stated in the question, so 27 satisfies it while the other options do not.

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