Question: There are 3 switches downstairs, each corresponding to one of the light bulbs upstairs. How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?
Answer: You turn on one light bulb. Leave it on for a while. Then, turn that one off and turn another one on. Go upstairs. One light bulb will be cold, one will be warm, and one will be on.
Question: There is a farmer who has three sons. Nearing his death, he asked his three sons to find two objects that can fill the room he's in. The one who can deliver will be chosen as his heir. So the oldest son goes to the market to get hay while the middle son go get leaves. The youngest son goes to a shop and buys two things that he put in his pocket. The oldest son's hay only fills half the room, the middle son's leaves fills 2/4 quarters of the room, while the youngest fills the room with his two objects. Question: What are the two objects that the youngest son used to fill the room?
Answer: A match and a candle.