By seanharris on Jul 31, 2007
There are two interconnecting rooms. In the first room that you are currently in there are three light switches. In the second room there is a light bulb. One of the three switches is connected to the light bulb and the other two are not connected to anything. You may pass from the first to the second room just once. When you arrive in the second room you must state accurately which switch controls the light bulb. It is possible to be 100% accurate. There is no way to be able to see into both rooms at the same time and there no way to operate the switches while looking at the light bulb. There is also no windows in either room (either in the walls or in the roof).