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Burning Time

Posted on January 27th, 2010 at 9:05 by John Sinteur in category: Puzzle -- Write a comment

[Quote:]

You have two one-hour fuses: If you light one, it will be consumed in exactly one hour.Unfortunately, they’re badly made — some sections of each fuse burn faster than others. You know only that each full fuse will burn in one hour.Using only these two fuses and matches to light them, how can you tell when 45 minutes have passed?

  1. yj on January 27th, 2010 at 16:48:

    light both ends of first fuse, and one end of 2nd fuse at the same time. 30 min later, first fuse (lit both ends) will burn out. At this point, light the 2nd end of 2nd fuse (still burning from one end). 15 min later, 2nd fuse will burn out. Total = 45 min.

  2. Mauro on January 27th, 2010 at 19:55:

    Ooh. yj, that’s clever. (:

    Hey, John, maybe you should come up with another category for puzzles? They’re not news. ;p I like them!

  3. John Sinteur on January 27th, 2010 at 19:56:

    Yeah… when I can’t think of a category, I just leave it defaulting to “news”. Perhaps I should rename it to “bog if I know how to call this” or something…

  4. JimM on January 27th, 2010 at 19:57:

    This was a puzzler on the NPR radio show “Car Talk” a year or 2 ago. Still, it’s neat.

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