Billboard Equation

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.

[ Car Talk Puzzler ]