A mother is 21 years older than her child. In 6 years, the mother will be 5 times as old as the child. How old is the child right now?
-0.75 years (or -9 months / about to be born)
Let C be the child's age: M = C + 21. In 6 years: M + 6 = 5(C + 6) => C + 27 = 5C + 30 => 4C = -3 => C = -0.75 years.
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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