A water lily doubles in surface area every day. If it covers a pond in 20 days, how many days did it take to cover one-quarter of the pond?
18 days
It covers the whole pond on day 20. On day 19, it is half. On day 18, it is a quarter.
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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