A patch of water lilies on a lake doubles in area every 24 hours. If it takes exactly 48 days for the patch to blanket the entire lake, on which day was the lake one-quarter covered?
Day 46
Since the patch doubles daily, working backward means the lake was half covered on Day 47 and one-quarter covered on Day 46.
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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