Gas Milage Part I

Let us do a fun math problem (this comes from a puzzler on Car Talk...I got it right, but didn't win).

A household has 2 cars, one is a hybrid getting 100 mpg (it's just awesome) and the other is a land yacht that gets 12 mpg. Each vehicle is driven the exact same distance in a given month. New technology has just become available that would allow the family (couple, whatever) to upgrade their hybrid from 100 to 200 mpg! It is pricy, however, and for 1/5th the cost they could tune up their yacht so that it would get 14 mpg. If they can not afford to do both, which one should they do (in terms of saving the planet/their wallet)?

***Jeopardy music plays***

Anyone who said they should ditch their land yacht is 100% correct...of course you get a big red X on your test sheet for this question. Those who said they should tune the leviathon are the ones who win the math star for today. There is an elagant solution, but I am not going to write it up here. I will say each car is driven (for example) 600 miles/month. Improving the hybrid will mean a savings of 3 gallons of gas/mo--from 6 gallons to 3. The tune up of the hulking street menace, on the other hand will save a bit over 7 gallons/mo--from 50 gallons to 42.8. In fact even if the tune up results in only 13 mpg it is still the better deal at savings of nearly 4 gallons/mo--50 to 46.2. The moral of this: the worse the milage a particular vehicle gets, the greater the impact of improving it's fuel efficiency, even marginally. So if we want to reduce fuel needs of this country which set of vehicles should we target to increase standards: passenger vehicles, light trucks and small SUVs, large trucks and SUVs?

To be continued...