Quote:
Originally Posted by sammyg2
You find yourself at the foot of a flight of stairs.
Next to you are three switches.
One of them turns on an incadescent light bulb in a room at the top of the stairs, but you can't see the light or any light from it unless you climb to the top of the stairs.
You need to determine which of the three switchs turns on the light but you are only allowed to climb the stairs one time.
How do you do it?
|
I'd flip on a switch and wait for a couple of minutes.
Then I'd flip it back off and flip on another switch and wait for about another 30 seconds.
Then I'd flip that switch off also and run up the stairs and into the room.
Then I'd touch the bulb to see if it was hot.
If it was hot, that would tell me that it was controlled by the first switch I flipped.
If it was warm, that would tell me that it was controlled by the second switch I flipped.
If it was cold, it's controlled by the switch that I didn't flip.
I was in this predicament when I was in Vegas last year. My biggest fear was that I'd run up the stairs and some character named Tabs would jump into the doorway and push me back down.