"A large drum filled with water contains 200 liters and including the drum weighs 220 kg. To move it you have to reduce the weight. What can you add to the drum to reduce it's weight and leave you with to only 40 kg?"
While walking Amy looks at an old photo of a person. Her friend asks her who the person in the photo is. Amy says: I don't have any brothers or sisters. But that woman's mother is my mother's daughter. Who is she?