Problem 4 · 2015 Math Kangaroo
Easy
Number Theory
place-valuedigit-sum
If you multiply both digits of the number 35, you get 15. How big is the sum of both digits?
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Answer: E — 8
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Hint 1 of 2
The two digits of 35 are 3 and 5; the problem already multiplies them.
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Hint 2 of 2
The question asks for the sum of those same two digits, not the product.
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Approach: read off the digits, then add them
- The digits of 35 are 3 and 5 (and indeed 3 × 5 = 15).
- Their sum is 3 + 5 = 8.
- So the answer is 8.
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