A father is currently four times as old as his daughter. In 20 years, he will be only twice as old as her. What is the daughter's current age?
10 years old.
Let daughter be x, father be 4x. In 20 years: 4x + 20 = 2(x + 20). Simplifying: 4x + 20 = 2x + 40 -> 2x = 20 -> x = 10.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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