I'm having a discussion about the following riddle with a friend.
There is a boy behind each girl, and a girl behind each boy. What is the smallest number of children required to do this?
I say the answer is 0, they say 2 (if they stand back to back). I think it's 0 because the statement is then automatically true and it was never stated that there was at least one child. Am I correct and is there an easy way to explain this?