Mr. Jones has two children. The older child is a girl. What is the probability that both children are girls?
Mr. Smith has two children. Either the older or younger one is a boy. What is the probability that both children are boys?
The answers are not the same.
It can also be asked in the following manner:
Mr. Jones has two children, Ashley and Reagan. The Ashley is a girl. What is the probability that Reagan ia a girl?
Mr. Smith has two children, Drew and Jamie. He has at least one boy. What is the probability that both children are boys?