Three runners—A, B, and C—cross a bridge together at the pace of the slowest runner, taking exactly 12 minutes. Runner B is twice as fast as Runner C, and Runner A is twice as fast as Runner B. How long would it take Runner A to cross the bridge alone?
3 minutes.
Since all three move together at C's pace (the slowest), Runner C takes 12 minutes alone. Runner B is twice as fast as C, taking 6 minutes. Runner A is twice as fast as B, taking 3 minutes.
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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