When a car zooms down the street too fast, that driver had better hope no police are watching, or they’ll give him a speeding ticket: a fine that speeders have to pay as punishment. But cops can’t be everywhere at once, so they can’t catch all speeders. Well, now cameras attached to traffic lights can measure cars’ speed and take pictures of the lawbreakers! Of course, those cameras also see the cars driving the right speed, and that gave TV producer Kevin Richardson a great idea: why not pay good drivers from the speeding-ticket money from the bad drivers? When the camera takes pictures of good drivers, their license plate numbers get put in a pile, and the lucky ones picked from that pile win $3000 each. When the city of Stockholm tried this Speed Camera Lottery a couple of years ago, the average speed on that road dropped from 20 miles per hour to 15, since people knew they’d pay for speeding but could win money for driving well. The idea won the FunTheory contest — and when you do the math, it’s a lot of money for the extra minutes you took to drive to lunch.
Wee ones: Who’s driving faster, a car at 13 miles per hour or a car at 12 miles per hour?
Little kids: If you zoom through 8 traffic lights with cameras and 1/2 of them snap a picture of you, how many cameras take your picture? Bonus: If the speed limit was 25 miles per hour and you were driving 5 miles per hour too fast, how fast were you driving?
Big kids: If you normally cross town in 12 minutes, but slow to 1/2 the speed so you can win the good-driver lottery, now how long do you take to cross town? Bonus: If you then win $3000 for your efforts, how much money did you make per extra minute on that trip? (Hint if needed: To divide by 12, which is 3×4, you can divide by 3, then by 4.)
Wee ones: The car at 13 miles per hour.
Little kids: 4 cameras. Bonus: 30 miles per hour.
Big kids: 24 minutes. Bonus: $250 per minute – not bad!