The Lawnmower Mystery

Apr 19, 2013

RAY: This week's Puzzler was sent in by Joe Barger. He writes, "My father, Max, at about age 65 still likes to mow his own lawn with a gasoline push mower (not self-propelled). He's had the same mower for 20 years. About a year or so ago, he noticed that the mower was not getting very good gas mileage. The mower was using much more gas than it used to per cut of the lawn.

So Max took the lawn mower to the neighborhood small-engine repair shop. They replaced a spark plug and spark plug wire, cleaned the carburetor, and installed a new air filter.

After all the repairs, Max took the new lawn mower home. But he noticed that the gas mileage had not changed a bit.

The engine and the lawn mower were in perfect working order. The lawn-mower service guys did nothing wrong, and there's nothing they overlooked.

TOM: The lawn isn't thicker than it used to be?

RAY: Nope. What's going on?


RAY: Here’s the answer. Now remember, at age 65, Max, seeing the loss of mileage with his lawn mower, has to do with one thing and one thing only. The only answer is one thing. Max is walking slower.

TOM: And I've noticed the same thing. It takes me more gas to mow my lawn now, because I walk slower than I did 10 years ago.

RAY: Of course. If you walk slower, of course it's going to take longer, because it's running doing nothing most of the time. At the worst case, it would take an infinite amount of gas.

TOM: If you couldn't walk at all, you'd start the baby up, and you'd stand there and say --

RAY: Well, that's what I do now. I look at it, and I say, go. Do we have a winner?

TOM: Yeah. We've got a winner, actually. Faith Hayes from Reno, Nevada.

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