You’re 40, she’s 10 – A classic Abbott and Costello skit, where Bud Abbott tries to play a prank on Lou Costello, only for Lou to use his clownish math skills.
Slicker Smith (Bud Abbott): You’re 40 years old and you’re in love with this little girl that’s 10 years old. You’re four times as old as that girl and you couldn’t marry her, could you?
Herbie Brown (Lou Costello): Not unless I come from the mountains.
Slicker Smith (Bud Abbott): All right- you’re 40 years-old, you’re four times as old as this girl, and you can’t marry her, so you wait five years. By that time the little girl’s 15 and you’re 45. You’re only three times as old as that little girl. So you wait 15 years and when the girl is 30, you’re at 60. You’re only twice as old as that little girl.
Herbie Brown (Lou Costello): She’s catching up.
Slicker Smith (Bud Abbott): Yes, yes. Now here’s the question. How long do you have to wait until you and that little girl are the same age?
Herbie Brown (Lou Costello): Now what kinda question is that? That’s ridiculous!
Slicker Smith (Bud Abbott): Ridiculous or not, answer the question.
Herbie Brown (Lou Costello): If I wait for that girl she’ll pass me up. She’ll wind up older than I am.
Slicker Smith (Bud Abbott): What are you talking about?
Herbie Brown (Lou Costello): She’ll have to wait for me!
Slicker Smith (Bud Abbott): Why should she wait for you?
Herbie Brown (Lou Costello): …I was nice enough to wait for her!