A lily pad doubles in size every day. On the 30th day, the lily pad covers the entire pond. On what day did it cover exactly half of the pond?
The 29th day
Since the lily pad doubles every day, whatever size it is on day 29 will double on day 30 to cover the whole pond. Therefore, it covered half the pond on day 29.
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: Easy. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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