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Three Light Switches Puzzle
Difficulty Level

three switches and three bulbs riddle

There are three switches in a hallway. One switch controls a light fixture in a room at the far end of the hall. The door to the room is closed, and you canno€™t see whether the light is on or off. You need to find out which of the three switches controls the light. You are allowed only one inspection. How can you be certain of finding out which switch controls the light?

View Answer Comments(1)

The main constraint is that you are allowed only one inspection.Let the switches be 1, 2, and 3.

Step 1 : Leave switch 1 off.
Step 2 : Turn switch 2 on for five minutes and then turn it off.
Step 3 : Turn switch 3 on and immediately enter the room.

If a bulb is on, it's controlled by switch 3. Feel the other lightbulbs for heat. A warm bulb is controlled by switch 2. A bulb that is off and cold is controlled by switch 1.

Guest Said:Posted On 2015-12-11

1St on one of the switch call it as "red" wait for sometime, switch it off. And on another switch call it as "orange". Call 3rd switch as green go to lights room, the light which is on is controled by orange, which is hot is controlled by red, and the remaining is controled by green