A professor remarks: 'I am an adult under 70 years of age. Exactly three years ago, my age was divisible by 8. Exactly three years from now, my age will be divisible by 7.' How old is the professor?
67
Three years ago, age was 67 - 3 = 64, which is divisible by 8 (8 * 8). Three years from now, age will be 67 + 3 = 70, which is divisible by 7 (7 * 10). Within adult ages below 70, 67 is the only valid solution.
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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