A patch of lily pads doubles in surface area every day. If it completely covers the surface of a pond on Day 48, on which day did it cover exactly 25% of the pond?
Day 46
Working backward: on Day 47 the patch covered half (50%) of the pond, and on Day 46 it covered half of that, which is 25%.
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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