Question:
One man shows another the portrait of a gentleman and tells him: I have neither brothers nor sisters, but this man's father is the son of my father. Who is the man in the painting?
Answer:
The gentleman in the portrait is the son of the man who is speaking.
Try another Brain Teaser:
A boy is 2 years old, his brother is half as old as him. When the first boy is 100, how old will his brother be?