A man who lives on the tenth floor takes the elevator down to the first floor every morning and goes to work. In the evening when he comes back, if it is a rainy day or if there are other people in the elevator, he goes to his floor directly. Otherwise, he goes to the seventh floor and walks up three flights of stairs to his apartment. Can you explain why?
Your last good ping-pong ball fell down into a narrow metal pipe imbedded in concrete one foot deep. How can you get it out undamaged, if all the tools you have are your tennis paddle, your shoe-laces, and your plasticwater bottle, which does not fit into the pipe?
An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower wins. After wandering aimlessly for days, the brothers ask a wise man for guidance. Upon receiving the advice, they jump on the camels and race to the city as fast as they can. What did the wise man say to them?
The man is of short stature. He can't reach the upper elevator buttons, but he can ask people to push them for him. He can also push them with his umbrella.
All the tools are random things that are not going to help you. All you have to do is pour some water into the pipe so that the ball floats up on the surface. And if you say that you don't have any water, then think about what you drank today and if you can use that somehow :-)
The wise man told them to switch camels. Their father never said that the sons had to ride their own camel — just that the son who owned the slower camel would win his fortune.