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Write one digit on each side of 36 to make a four-digit multiple of 36. How many different solutions does this problem have?

User Kavigun
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1 Answer

3 votes

9514 1404 393

Answer:

3 solutions: 1368, 5364, 9360

Explanation:

In order to be divisible by 36, the number must be divisible by 9 and by 4. The number will be divisible by 9 if the sum of its digits is divisible by 9. 36 already has a digit sum of 9, so the two added digits must sum to 9.

The number will be divisible by 4 if the least-significant digit is a multiple of 4. That is, it must be 0, 4, or 8. Then the corresponding most-significant digits must be 9, 5, or 1.

The three solutions are ...

1368 = 38 · 36

5364 = 149 · 36

9360 = 260 · 36

User Willemijn
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