Question: A girl went to school, and her teacher asked her how old she was.
Girl: I don't know, but I know I'm half my mother's age
Teacher: how old is your mother
Girl: I don't know, but she is 5 years younger than my dad
Teacher: how old is your dad
Girl: I don't know, but if you add all our ages, they count up to 100.
How old is the girl, mother, and dad?