Question: Tom wants to send Sally an expensive ring through the mail because they live thousands of miles apart. The only problem is that everything sent through the mail is stolen unless there is a lock put on it. Both Tom and Sally have plenty of locks and keys but they don't have any of the same locks or keys.
How can Tom send Sally the ring without it getting stolen?
Answer: Tom puts one of his locks on the box with the ring in it. When Sally gets it she puts one of her own locks on the box and sends it back to Tom. Finally Tom takes his lock off of the box and sends it back to Sally who can then unlock her own lock and retrieve the ring.
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.