On the wall of the first floor of a house there are 3 switches all in the off position. One of these switches turns on the light on the second floor; two control nothing. By flipping the switches however you like, and by being only allowed one visit upstairs, determine which switch controls the light. (you cannot see the upstairs from the switch and noone else is in the house).
2007-02-04 14:53:27 · 4 answers · asked by ClooneyIsAGenius 2 in Science & Mathematics ➔ Mathematics
Turn two switches on. Wait a while. Turn one of the switches off. Go upstairs and check the light.
If the light is on, then it's the switch that you left on. If the light is off but warm, then it's the switch you turned on and then off again. If the light is off and cold, then it's the switch you never touched.
2007-02-04 14:57:28 · answer #1 · answered by Tim P. 5 · 1⤊ 0⤋
Well, Clooney, no one else is inside the house, but someone might be standing outside the house, who can see all the floors of the house clearly. So, when I switch on the correct switch, my friend waiting outside would tell me that the light on the 2nd floor has been turned on. So, that's how I determine the correct switch by paying only one visit upstairs.
2007-02-04 23:03:57 · answer #2 · answered by Kristada 2 · 0⤊ 0⤋
Impossible.
Flip 0: won't help because light will be off
Flip 1: if the light is off you won't know which of the other 2 will turn it on and which will be useless
Flip 2: if the light is on you won't know which of the 2 you flipped turned it on and which was useless
Flip 3: won't help because light will be on
2007-02-04 22:59:04 · answer #3 · answered by Anonymous · 0⤊ 0⤋
I was going to suggest taking off the switch cover and figure out which one is connected to the wire, but the first answer is alot more practical and probably easier.
2007-02-04 22:59:46 · answer #4 · answered by Anonymous · 1⤊ 0⤋