Friday, June 20, 2008

A Practical Application of Pre-Algebra Math

Especially given today's gas prices, this story is extremely interesting.

"There is a math illusion here," said Richard Larrick, a management professor at Duke University, whose research appears in the journal Science.

Larrick said most people think improvements in miles per gallon are all the same, where a 5 gallon per mile improvement would yield the same gas savings in a car that gets 10 miles per gallon or 20 miles per gallon. (One mile equals 1.61 kilometers, and one U.S. gallon equals 3.79 liters.)

"The reality that few people appreciate is that improving fuel efficiency from 10 to 20 miles per gallon is actually a more significant savings than improving from 25 to 50 miles per gallon for the same distance of driving," Larrick said.

Go read the whole thing. It's very interesting--and simple to understand.


Curmudgeon said...

Sorry, but I disagree this is readily understandable. This article is tailor-made to screw with the math-phobic. Inconsistent points mixed with really bad quotation (or note-taking) skills

On the other hand, it's going into my pre-algebra file for the kids next year. They'll also have to re-write the article for clarity and re-create the table.

"most people think improvements in miles per gallon are all the same, where a 5 gallon per mile improvement ..."

Damn. 5 gallons per mile BETTER? What is this, a freight train?

Then the article suddenly changes from talking about comparing gals/100 miles to a calculation for gals/10000 miles.

Then we have reporting like this: "Cars with the highest miles per gallon are always the most fuel efficient, he said." Wow. I guess that's why the management professor at Duke University gets the big bucks.

Fritz J. said...

I agree with Curmudgeon. I understand the concept of diminishing returns, but reading that article is not the best presentation of it that I've seen. I don't know whether to blame the Duke professor or the Reuters writer for the lack of clarity. I suspect that the Reuters writer is the problem, but have nothing to base that on other than the observation that journalists frequently foul up what they write about.

Anonymous said...

Skip Reuters and try the original Science article and supplement:;320/5883/1593/DC1

Eowyn said...

I think the whole point the article tries to make is nonsensical. They seriously seem to argue that the 28mpg choice is the best one, because of the increase over the 18mpg.

The key point is not how much you improve, but how many gallons overall you're using, and by that (much more useful and important) metric, 50mpg will win every time.

The whole story seems designed to make people feel good about improving their lousy mpg to acceptable mpg.