And the Winner Is.....

Rod! of Flockfold Kids! with the answer to trade the minivan. Several of you came to that conclusion, but Rod had an element in his answer that the radio story suggested: that our vehicles should be rated in gallons per mile, not miles per gallon if we are to save gasoline.

Remember, you were given that:

1. The vehicles are driven the same number of miles per year.
2. There was no mention of load and it is to be assumed the same load - i.e. you don't haul feed bags in your minivan, weighing it down.
3. How "cool" the vehicle looks while being driven isn't a factor.

The only objective was to save gasoline. To get this answer, Rod converted the miles per gallon of the minivan (18), the station wagon (28), the sedan (30), and the hybrid (50) to gallons per mile: 0.056, .036, .033, and .020 respectively.

There were two possible combinations, the minivan with the hybrid, and the station wagon with the sedan. By looking at the gallons per mile, you get .056 + .020 = .076 gallons per mile if you keep the minivan, and .036 + .033= .069 gallons per mile if you trade the minivan. As Rod says, "bye-bye, Eugene". You use less gallons per mile (.069 versus .076).

Neither miles driven nor the price of gas was necessary to determine this answer of reducing the number of gallons of gasoline used. Of course, in real life, it is more complicated - highway versus city driving, who is in the car, maintenance of the car. All things being equal though (as in this problem), we could reduce our oil consumption by getting the biggest gas guzzlers off the road as soon as possible.

So, congratulations, Rod, winner of the McD's gift card! Bon appetit!