I posted a riddle last week. Are you ready for the answer?
OK, so you have three light switches in one room and only one of them controls a light bulb in another room. From the light switches you cannot see the light bulb or any evidence of it being on or off. You can turn on and off the switches as often as you want, but you may only go into the room with the bulb once. How do you figure out which switch is the right one?
You turn on the first switch and leave it on for a minute. Turn it off, then flip the second switch and immediately go to the light bulb. If the light is on, of course the second switch controls the bulb. If it is off, touch the bulb to feel for heat. If it is hot, then the first switch controls the bulb. And, by process of elimination, a cool dark bulb would be controlled by the third switch.
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