Light Bulb Dilemma
Riddle: There are three switches that go to three light bulbs in another room. You need to figure out which switch goes to which bulb. You can flip any of the the switches any amount of times, but you can only check the light bulbs once. How do you do this?
Answer: Turn the first switch on. Keep the second switch off. Turn the third switch on for five minutes then turn it off. When you go in the other room, the lit bulb goes to the first switch. Then, touch the off bulbs. If it is hot, it belongs to the third switch. If cold, it goes to the second switch.
Source: https://www.riddles.com/5155
