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?

you're standing outside. you flip the first switch on. Wait a minute, then turn it off. Then flip the second switch on and walk in the room. If the light is off its not the second switch. If you feel the lightbulb and its cold, it's not the first switch so it much be the third. If the lightbuld is hot then its the first switch.. makin sense?

lightbulb
hot and off= first switch
on= second switch
cold and off= third switch

Posted by Mel on 2002-08-22 11:44:08