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You are standing outside of a room with no windows. The room has three light bulbs and three switches outside of the room. Each switch controls one of the light bulbs. You may only enter the room one time. How can you find out what switch goes to each light bulb?
This puzzle is not quite as ‘pure’ as the other question in that it doesn’t boil down to a mathematical model. Because it’s such a prevalent question, it’s worth taking a quick look at…
I hope the below answer is the best.
• Turn on switches 1 and 2, then wait a few moments and then turn off the 2nd switch.
• Walk into the room and find whichever bulb is turned on is connected to switch 1, Touch the switched off bulbs and which is turned off and hot is connected to switch 2, and the third is connected to switch 3.