In article <37m4k7$1pp@nippur.irb.hr> of rec.puzzles, Zeljko Vrba
<zvrba@public.srce.hr> wrote:
You are outside the room. In the room there is a lightbulb. Outside the
room are three (3) switches. How can you determine which of the switches
turns the light on if you are allowed to enter the room only once,
closing the door on your way out?