It's a mystery...

I once read a book called “Just For the Fun of It” by Carl Goerch.  It was written in 1954 I believe. Anyway, this is just one of the many riddles and fun stories he had to tell. 

Her Name Was Margaret 

Hal Trentman, of the Occidental Life Insurance Company, put this one up to us:

A man by the name of Brown left Chicago and went out to the Pacific Coast. He stayed out there twenty years. Then he returned to Chicago on a visit. The second day he was there he ran into an old friend on State Street. They stopped and reminisced.

“By the way,” said the friend, “I’ve got married since you left Chicago. This is my little girl: I’m taking her into the drugstore to get her an ice cream soda.”

Brown turned to the little girl and said: “What’s your name, Honey?”

And the child said: “My name is the same as my mother’s.”

Whereupon Brown said: “Oh, your name is Margaret also, is it?”

The child nodded and said: “Yes, sir.”

Now then: in view of the fact that Brown did not know whom his friend had married, how did he know the child’s name was Margaret?

It isn’t a catch problem: it is perfectly logical and there is a perfectly logical answer to it.

See if you can work it out.