I am a two-digit prime number whose digits add up to 8. If you reverse my digits, I produce another prime number larger than myself. What number am I?
17
Two-digit pairs summing to 8 are 17, 26, 35, 44, 53, 62, 71, and 80. The primes among these are 17, 53, and 71. Reversing 17 gives 71 (also prime and larger). Reversing 53 gives 35 (not prime). Thus, the number is 17.
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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