Three friends of mine (Albert, Bert and Charles) married three girls (Daphne, Elaine and Francine) but I didn't know who married whom. I asked a mutual acquaintance about the marriages, and he said:

"Well, work it out. If Albert married Elaine, then Bert married Francine, and vice versa."

I said, "That's not enough; can you give me other hint?"

"Right. Either Bert married Daphne and Charles married Elaine, or neither of these couples happened."

"Still not enough, give me something else."

"Let's see... Charles married Francine if and only if Albert married Daphne."

"You are still not helping. Couldn't you tell me at least one specific couple, any one, so I can work out the other two myself?"

He smiled. "That wouldn't help you."

I thought a little, and I knew the three pairs. Who married whom?

Not possible 1:
Albert could not be married to Daphne, because then Charles would be married to Francine, leaving Bert married to Elaine which could not happen because this condition can only be satisfied if Albert is married to Francine.

Not possible 2:
Bert married Daphne and Charles married Elaine is not possible because Albert could marry Francine only if Bert marrie Elaine.

Possible:
Albert married Elaine and if this happens Bert married Francine leaving Charles married to Daphne.

Posted by Solomon on 2005-07-30 23:35:17