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Light a fuse

Logic puzzles require you to think. You will have to be logical in your reasoning.

 

Puzzle ID:#697
Fun:*** (2.42)
Difficulty:*** (2.57)
Category:Logic
Submitted By:link2440**
Corrected By:sdm1177

 

 

 



You have 2 fuses. One fuse burns for 1 hour, the other burns for 2 hours. The problem is that the fuses burn irregular. The last few inches may burn longer than first few inches. Using the 2 fuses how can you create a fuse that burns for exactly 45 minutes. Remember, cutting them does no good since you don't know how long the cut fuse lasts.


Answer

You burn both sides of the 1 hour fuse and 1 side of the 2 hour fuse at the same time. Regardless of the varying speeds of the one hour fuse, when it goes out it has been 30 minutes. At that point there would be 1 hour and 30 minutes left on the 2 hour fuse. You then light the other end of the 2 hour fuse and since the burning time would be cut in half the fuse would be 45 minutes long.
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