Puzzles/Non-scientific puzzles/Boy and Girl

Puzzles | Non-Scientific Puzzles | Boy and Girl

A boy and a girl are talking.


 * "I am a boy" - said the child with black hair.


 * "I am a girl" - said the child with white hair.

At least one of them lied. Who is the boy and who is the girl?

If only one of them had lied, we'd have to conclude that both are boy or both are girl. This is impossible, so both of them must have lied. Therefore, the child with the black hair is the girl, and the child with the white hair is the boy.