*Behind curtain #1 is a devilish math test*

Monty Hall, the late host of “Let’s Make a Deal,” may not be the first person who comes to mind as someone associated with complicated probability theory. But to mathematicians, he’s as well known as Stephen Hawking, Katherine Johnson, or even the jerk responsible for so many unfortunate results on my geometry tests: Euclid.

This fame derives from the “Monty Hall Problem.” My son told me, “anyone with a passing interest in math has heard of it.”

Naturally, I hadn’t heard of it.

But Monty Hall will be known for the Monty Hall Problem long after his TV show is forgotten, like Arnold Palmer will be known as a drink, not a golfer.

It’s a problem to explain the Problem, but I’ll try. In “Let’s Make a Deal,” contestants are asked to choose what’s behind one of three curtains. Behind one of them, there’s a big prize. Behind the other two, a clunker, often a goat.

However, before he would reveal whether you chose correctly or not, Monty would reveal what was behind one of the other curtains that was not the new Ford Mustang convertible or trip to fabulous Puerto Vallarta. And then he’d ask you if you wanted to stay with your choice, or switch to the other remaining curtain.

He’s trying to trick you, right? With two curtains remaining, the odds are obviously 50/50. Why change and be embarrassed when the goat appears?

Here’s why. Because if you do change, you have a two-in-three chance of winning. And that is what makes people’s head explode, mine included.

How can this possibly be correct?

Apparently, and I say apparently because I don’t fully understand it, it’s because Monty knows what’s behind each door. And he’s removing a goat for you. So if you stay, you have your original one in three odds. If you change, acting on that new information, your odds improve considerably.

That’s the best I can do, people. I dropped math after the 10th grade.

By the way, no one understood the Monty Hall Problem better than Monty Hall. He surely liked math. He had a B.S. degree in chemistry and zoology. Monty and a partner got rich developing and producing “Let’s Make a Deal,” so at a minimum he got good at counting.

Beyond being smart, he was nice—Canadian, like Alex Trebek—and helped raise over a billion dollars for charity.

Hall didn’t see the problem from a purely mathematical standpoint, because he knew he didn’t always play by “the rules.” He could make or not make the offer to switch depending on how he was feeling that day. It kept things fresh, and he didn’t have a problem with that, or with the math behind knowing which curtain to pick.

After all, “Let’s Make a Deal” was all about math. What are the odds you can do better by trading for something else? If you had a head for figures, you could make out pretty well on that show, then and now.

My best case scenario? I wind up with a goat.

## Comments

You can follow this conversation by subscribing to the comment feed for this post.