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There are 3 switches in a room and a bulb in another room far away. One of the switches turns the bulb on. How can you find the switch which turns the bulb on by going to the room only once?


marked as duplicate by generalcrispy, Matt, F1Krazy, QuantumTwinkie, Deusovi Mar 13 at 16:05

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  • $\begingroup$ Might as well be. The solution is exactly the same. Instead of 3:3, it's 3:1. $\endgroup$ – generalcrispy Mar 13 at 15:51
  • $\begingroup$ This is a similar question but not the same as there is slightly more logic to it. The question is not clear on the type of light source, led, filament or fluorescent. Assuming it is a bulb that gets hot to touch, then the solution is: Turn on two switches, wait for 10 minutes or so, turn off one switch, go to the room, if the light is on then it is the switch you left on. If the light is off but the bulb is hot, then it is the switch you turned on then off. otherwise it is the other switch that you did not touch. $\endgroup$ – 5202456 Mar 14 at 13:01

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