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Light bulb (Posted on 2002-05-16) Difficulty: 2 of 5
A light bulb is hanging in a room. Outside of the room there are three switches, of which only one is connected to the lamp. In the starting situation, all switches are off and the bulb is not lit.

You are allowed to enter the room only once (the bulb is not visible from outside). How can you determine which of the three switches turns on the light bulb?

See The Solution Submitted by Half-Mad    
Rating: 3.2500 (24 votes)

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Some Thoughts Solution... Kind of... | Comment 13 of 17 |

I've heard of a puzzle like this before, where there were three lights instead of one... but here goes!

I think that  you need to turn all of the lights on, but at different times with about half-an-hour in between, then go into the room after about another half-hour. So long as the bulb isn't some last-super-super-long ones, you should be able to judge depending on the temperature which switch is THE switch.

  Posted by Stephen Ticsay on 2005-04-15 01:37:27
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