Tuesday, July 28, 2009

Puzzle: Mosquito Coil and Time

Few months ago, my brother came home with a puzzle from his NDU camp that made everyone in the family cracked our head.

It is something made up over mosquito coils. (It's interesting what a bunch of army boys can come up with when they have nothing to do.)

PUZZLE:
One mosquito coil takes 1h to burn.
(A) How to measure exactly 30 min using one coil?
(B) How to measure exactly 15 min using two coils?

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2 comments:

  1. BenDecember 14, 2009 at 5:47 PM

    To measure 30 mins simply burn the coil from both ends, when the 2 ends meet 30 mintues will have passed.
    To measure 15 minutes, set 1 coil burning from 1 end and the other burning from 2 ends all at the same time. When 30 mins have passed the coil burning from both ends will finish burning. At this time light the non-burning end of the remaining coil. It will be 15 mins from this point when those 2 ends meet.

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  2. unknownApril 5, 2021 at 2:58 AM

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