A water lily doubles in size every day. If it takes 20 days to cover the entire pond, how many days did it take to cover exactly half the pond?
19 days
Since the lily doubles every day, whatever state it was in on day 20, it would be exactly half that size on day 19.
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: Easy. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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