Two girls went to dinner together and both ordered iced tea. One girl pounded down five of them in about a minute, and the other took her time drinking one. The girl who drank one died, while the girl who drank five survived. However, all of the drinks that were served turned out to contain poison. Why did the girl that drank more iced tea survive?
There is a windowless room with only a single door. Inside the room is a lamp, when the lamp is on no light escapes the room. Outside the room are 3 switches one of which operates the lamp. You can use the switches in any order any number of times. The door can only be opened once and after you enter the room you can immediately know which switch turns on the light. How is it possible?