The Washington Post quoted a National Academy of Sciences panel in its July 31, 2001 paper: "Making vehicles more efficient would add to their sticker prices, but that cost would be offset by saving on fuel. A small SUV, for instance, could average 26 percent better mileage for an upfront cost of $818. ...Classified as light trucks, SUVs and minivans currently are required by the Department of Transportation to get an average of 20.7 miles per gallon."

Assuming that the average person drives her SUV 15,000 miles in a year, and that gas costs $1.49 per gallon, and that SUVs currently get 20.7 mpg, how many years would it take for the SUV to recoup its initial cost of $818 to improve its gas mileage by 26 percent?



Solution:
The answer is 3.67 years or 3 years and 8 months.

Currently, an SUV which travels 15,000 miles at 20.7 mpg would use 724.637 gallons of gasoline in a year. At $1.49 per gallon, the cost for gas in a year is $1079.71.

If the $818 worth of improvements are made so that you get 26% better gas mileage or 26.082 mpg, traveling 15,000 miles would only require 575.1 gallons of gas in a year. The cost for the gas would be $856.90, or an annual savings of $222.81.

It would, therefore, only take $818 / $222.81 = 3.67 years to recoup the money spent for improvements.

However, in the August 2, 2001 edition of The Washington Post, the House rejected a proposal to boost fuel efficiency standards for sport utility vehicles.




Correctly solved by:

1. Geof Keith Santa Monica, California
2. David and Judy Dixon Bennetsville, South Carolina
3. Keith Mealy Cincinnati, Ohio
4. Richard K. Johnson La Jolla, California
5. Malcolm Harris West Malling, Kent, United Kingdom
6. Bill Hall Wellington, Florida
7. John C. Funk Ventura, California
8. Barbara Hall Wellington, Florida
9. Kirstine Wynn Winchester, Virginia
10. Joe Heintz Manchester, Tennessee