How Old Are You?

A woman was having some trouble with her heart, so she went to the doctor. He was a new doctor, and did not know her, so he first asked some questions, and one of them was, ‘How old are you?’

‘Well,’ she answered. ‘I don’t remember, doctor, but I will try to think.’ She thought for a minute and then 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. That is thirty-six, isn’t it?’

(L.A. Hill, Elementary Stories for Reproduction, Oxford University Press)