The Monty Hall Puzzler
New Puzzler, 10/11/97: Behind Door Number One...
RAY: OK. Now, here's the puzzler for this. I thought about this a lot and I have a whole bunch of puzzlers, but I have to revisit this puzzler, from yesteryear, for a variety of reasons. Number one --
TOM: I know one of them. You found out the right answer.
RAY: Number of reasons plus one.
TOM: Plus one.
RAY: Number one it was perhaps, it is perhaps one of the best puzzlers of all time, I think.
TOM: Monty Hall?
RAY: Number two, we haven't used it in so long that the people that heard it then, are dead.
TOM: They're dead. Or they forgot.
RAY: Here it is, in its simplest form.
RAY: You may remember the game show. What was that game show? Let's Make a Deal.
TOM: Let's Make a Deal. Yeah.
RAY: Where the contestant was presented with three doors - door number one, door number two and door number three. Behind one of the doors was a wonderful prize and behind the other two doors were crummy prizes, known as zonks.
RAY: And very simple.
TOM: Like a couple of candy bars or some such thing.
TOM: Something not worth much.
RAY: Exactly. A '63 Dodge Dart. Anything like that. Here's the deal. You are the contestants.
TOM: I'm the contestant.
RAY: Monty Hall says, "Pick a door." Your chances of picking a zonk are two and three and your chances of picking the winner are one in three.
RAY: He says, "OK. You pick door number two. I'm going to show you what's behind one of the doors that you didn't pick. Now, because there are two zonks and one winner and he knows where the winners and the zonks are. He shows you one of the doors that you didn't pick that's clearly a zonk.
TOM: So, he says, "I'm going to show you what's behind door number one."
TOM: And he looks behind door number one --
RAY: And it's six candy bars.
TOM: Six candy bars.
RAY: He then says to you, "Would you like to keep door number two, which you've chosen or would you like to switch to door number three?" That's the question - should you switch or not switch? Now, if you think you know the answer or just feel sorry for the Post Office in this age of e-mail and you want to give them something to do, send your answer to Puzzler Tower, Car Talk Plaza, Box 3500, Harvard Square, Cambridge --
TOM: Our fair city.
RAY: MA 02238. Or, if you prefer, you can e-mail us your answer from the Car Talk web site. Just click on the Talk to Car Talk section. Now, if we choose your correct answer at random, from among all of the correct answers that we receive, you will get a Car Talk sistine wrench T-shirt. Car Talk's first attempt, and probably last, at fine art.
TOM: And we don't say when you'll get it. You will get it.
RAY: You shall get it. You might.
TOM: At some time --
RAY: You probably will.
TOM: At some time in the future.