Solve this problem:

Question

Your in a room with one door that leads to a passage into another room. The room you are in has 3 light switches. The room down the passage has 3 lights. You may only open the door to each room once. You must close it when you open it. How would you tell which light switch turns on which light in the other room?

Answer 1

I switch one button and let it like that during 10-15 minutes, then I switch it off, switch another one on and immediately go to the room. The light bulb which is powered up is the one from the second switch, the light bulb which is powered off but still hot is the one from the first switch