I am a two-digit number. If you reverse my digits, my value increases by 54. The sum of my two digits is 10. What number am I?
28
Let the number be 10t + u. Reversing digits gives 10u + t. The difference is 9(u - t) = 54, meaning u - t = 6. Given u + t = 10, solving the system gives u = 8 and t = 2, so the number is 28 (and 82 - 28 = 54).
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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