If 7 cats kill 7 rats in 7 minutes, how many cats are needed to kill 100 rats in 100 minutes?
7 cats
Each cat kills 1 rat every 7 minutes. Over 100 minutes, a single cat can kill 100 / 7 rats? Wait: in 7 minutes 1 cat kills 1 rat. In 100 minutes, 1 cat kills 100/7 rats. To kill 100 rats in 100 minutes, you need 7 cats because each cat handles 14 and 2/7 rats? Let's check: 7 cats working for 100 minutes would kill 7 x (100/7) = 100 rats. Yes! 7 cats.
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: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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