A woman was having some trouble  with her heart, so she went to see a doctor. He was a new doctor, and did not know her, so he first asked some questions about her, and one of them was, "How old are you?" "Well," she said, "I don't remember, doctor, but I will try to think." She thought for a moment and said, "Yes, I remember now, doctor! When I married , I was eighteen years old, and my husband  was thirty. Now my husband is sixty, I know, and that is twice thirty. So I am twice eighteen. I think I am thirty-six,is it right?" Which is the best title  for the passage?
A Maths Problem. A Woman and Her husband. How Old Is She? A Clever Doctor.