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You know there is a default future waiting for you and if you do not do something different, you also know it is heading right for you.

Are you ready to tranform yourself?    My goal is to provide ideas that might show you some ways to write a better future for yourself, your family, yur work and the world!

Terry O is the Editor and Publisher of Uptime Magazine and Reliabilityweb.com

http://www.reliabilityweb.com

@reliability

# The miles per gallon illusion (Miles per gallon vs. gallons per mile)

The above image is taken from the article, available at www.sciencemag.org with subscription
From a recent post at bunnie’s blog that reads:

Here’s an interesting question.

Suppose you had a household with two cars, and each car needs to be driven 10,000 miles per year. One car consumes 34 MPG, and the other car consumes 18 MPG. Since gas is expensive, you want to replace one car. Because of utility constraints, you have two choices:

Replace the 34 MPG car with a 50 MPG car — a 16 MPG improvement Replace the 18 MPG car with a 28 MPG car — a 10 MPG improvement Which car replacement would save you the most gas? Normally, I consider myself not bad with quantitative comparisons like this, yet initially I picked the answer of replacing the 34 MPG car with the 50 MPG car based on the superior 16 MPG improvement. Another seemingly more analytical approach also leads to the same conclusion: 50 + 18 MPG giving a 34 MPG household average seems more efficient than 34 + 28 MPG giving a 31 MPG household average. This very interesting article in Science, “The MPG Illusion” by Richard P. Larrick and Jack B. Soll at the Fuqua School of Business in Duke University (Vol 320, June 20, 2008, p. 1593), points out the mathematically obvious truth that gas used per mile is inversely proportional to miles per gallon, which means that you have a steeper slope at lower MPG ratings, and diminishing returns at higher MPG ratings.

When you run the numbers, replacing the 34 MPG car with a 50 MPG (a 16 MPG improvement) car saves you 94.1 gallons per 10,000 miles, whereas replacing the 18 MPG car with a 28 MPG (a 10 MPG improvement) car saves you 198.4 gallons per 10,000 miles — more than double the savings.

Or, to give an even more clear-cut example, replacing a 5,000 MPG car with a 10,000 MPG car saves you just one gallon of gas, whereas replacing a 1 MPG car with a 2 MPG car saves you 5,000 gallons of gas, using a fixed mileage of 10,000 miles driven for comparison.

There are some important policy implications of this.