A dealer offers to you to play a game. He shows you three two-sided cards: one with both sides red, one red and black and the other black and black. He puts them in a hat, and randomly (no tricks here) takes out a card and puts it on the table.

You both see only one side of the card. At this point he says that if the bottom side is the same as the top, he will take your money. If the other side is different, you double it. He explains that by now one of the cards is ruled out - if you're seeing red, the card cannot be a double black card, and vise versa - so you have a 50/50 chance of winning.

Is this a fair game? Why or why not?

Ok, so you see one side of a card and you therefore know that it is one of two cards. Doesn't change the fact that the card is drawn from a pool of 3 cards, two of which cause you to lose. Since your money is only doubled, you lose out overall.

Posted by David on 2002-05-12 09:33:08