Billboard Equation

Feb 28, 1998

RAY: The new puzzler.

TOM: Oh, you have one?

RAY: I do have one.

TOM: I can hardly wait.

RAY: Well, I have a Crusty puzzler which I will save until next week.

TOM: I can hardly wait. What is it?

RAY: Well, this was sent to us from cyberspace by Roy Richarde.

TOM: Good. Read it.

RAY: It says --

TOM: Hurry up.

RAY: While driving around Luxembourg, on a recent trip to Europe, I caught a glimpse of a billboard that immediately brought Car Talk to mind.

TOM: Yeah.

RAY: The billboard was brightly colored with a cartoon like a pig on the bottom, but it wasn't just a pig that brought Car Talk to mind. Across the center of the sign was written an equation. Write this down.

TOM: I'm going to write it down. Go ahead.


TOM: D. Small or big.

RAY: Yeah.

TOM: D equals --

RAY: Equals V over 10.

TOM: Yeah.

RAY: In parentheses. Squared. That quantity squared. The whole thing divided by two. OK? You got it. So, the quantity --

TOM: Whoa!

RAY: V over 10.

TOM: Yeah. Square.

RAY: Squared. Divide V by 10, square it. You divide that whole thing by 2. Got it?

TOM: I've got it. Yeah.

RAY: Right? You got it?

TOM: Yeah. And this was a billboard?

RAY: This was a billboard. He says, remembering a discussion on the show of several months ago, I immediately knew what this was all about.

TOM: Wow!

RAY: What was it?

TOM: That's it? That's the question? No, oh, you gave a hint. Remembering a discussion on our show.

RAY: Remembering a discussion on Car Talk of a few months ago.

TOM: I knew immediately what this meant.

RAY: And all the hints are there. I mean Luxembourg. I mean you name it. You name it. It's all there, man.

TOM: Richarde.

RAY: Roy Richarde. Luxembourg. Europe.

TOM: Yeah.

RAY: D. D is there.

TOM: V. V is there too.

RAY: D and V. They're both there.

TOM: All right.


TOM: First of all, I am struck by the fact that any country would think that there were enough people driving around who would even know that it was an equation about anything.

RAY: Well, you know I was reading an article in the paper recently about how poorly American kids scored in science and math tests.

TOM: Yeah.

RAY: They were like 97th out of 91 of all the nations tested, and all the European nations typically do much better. I looked for France and they were unfortunately right up there, but Europeans in general, I guess, were a lot more literate in mathematics than we Americans are.

TOM: I guess so.

RAY: And what this equation means is that the distance that you should trail another car on the highway is determined by taking your velocity in kilometers per hour.

TOM: Yeah.

RAY: Let's say it's a 100.

TOM: Say it's a 100 kilometers per hour.

RAY: Which is 60 miles an hour in our lingo.

TOM: Yeah.

RAY: Divided by 10.

TOM: OK. So, that gives me 10.

RAY: Square that.

TOM: Square that. There's two. There's a 100.

RAY: Divide that by two.

TOM: There's 50.

RAY: Yeah. So, of course, the units are all wrong, but that's all right.

TOM: That's all right, but it means if I were driving at a 100 kilometers per hour, which is 60 miles per hour, I should be 50 meters or 150 feet --

RAY: Roughly.

TOM: Roughly behind the car in front of me.

RAY: There you go. Cute, huh?

TOM: Wow!

RAY: All right. What's the equation? Do you remember it?

TOM: D equals V over 10 squared, all over two.

RAY: Of course, while most people were trying to do the math, they'd crash into another car. And who's our winner anyway? We have a fabulous prize and who got it, Tommy?

TOM: The winner is from Luxembourg, someone named Diane Swan, from Eeston. E-E-S-T-O-N. Not eastern, but East-ton, Maryland.

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