A conference room contains three separate wall-mounted spotlights?!
Question: - right, left and front of stage. Each is controlled by its own on-off switch. These three switches are numbered 1, 2 and 3, but they are in a back-room which has no sight of the the spotlights or the conference room (and there are no reflections or shadows or mirrors, and you are alone). How do you identify each switch correctly - right, left, front - if you can only enter the back-room once?
Answers: - right, left and front of stage. Each is controlled by its own on-off switch. These three switches are numbered 1, 2 and 3, but they are in a back-room which has no sight of the the spotlights or the conference room (and there are no reflections or shadows or mirrors, and you are alone). How do you identify each switch correctly - right, left, front - if you can only enter the back-room once?
Switch on number 1 and leave it on for 30 seconds, then switch it off. Switch on number 2 and leave it on. Enter the conference room. The spotlight that is on is obviously number 2. The spotlight that is warm is switch 1, and the other spotlight is number 3!!!
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