Question 766591: Please help me solve this puzzle "If there are 3 switches outside the room corresponding to 3 bulbs inside the room, how will you know which switch belong to which bulb. Only once you can enter in room."
Found 2 solutions by Edwin McCravy, AnlytcPhil:
Answer by Edwin McCravy(20056)   (Show Source):
You can put this solution on YOUR website! Please help me solve this puzzle "If there are 3 switches outside the room corresponding to 3 bulbs inside the room, how will you know which switch belong to which bulb. Only once you can enter in room."
1. You turn switches 1 and 2 on.
2. Wait a few minutes.
3. You turn switch 1 off, leaving switch 2 on.
4. You open the door.
5. You will find:
One bulb is on. That bulb is controlled by switch 2, the only
switch that is on.
6. You feel the bulbs that are off. One is warm and the other is cold.
The bulb that is off and warm is controlled by switch 1, for switch
1 was on long enough to warm up the bulb it controls.
The light that is off and cold is controlled by switch 3, for switch 3
has not been turned on at all.
Edwin
Answer by AnlytcPhil(1806)  (Show Source):
You can put this solution on YOUR website! Please help me solve this puzzle "If there are 3 switches outside the room corresponding to 3 bulbs inside the room, how will you know which switch belong to which bulb. Only once you can enter in room."
1. You turn switches 1 and 2 on.
2. You wait a few minutes.
3. You turn switch 1 off, leaving switch 2 on.
4. You open the door.
5. You will find:
One bulb is on. That bulb is controlled by switch 2, the only
switch that is on.
6. You feel the bulbs that are off. One is warm and the other is cold.
The bulb that is off and warm is controlled by switch 1, for switch
1 was on long enough to warm up the bulb it controls.
The light that is off and cold is controlled by switch 3, for switch 3
has not been turned on at all.
Edwin
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