A mother is 4 times as old as her son today. In 20 years, she will be exactly twice as old as he is. How old is the son right now?
10 years old
Let the son's current age be s, so the mother's current age is 4s. In 20 years, 4s + 20 = 2(s + 20). Expanding gives 4s + 20 = 2s + 40, so 2s = 20, which gives s = 10.
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: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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