## Saturday, March 30, 2013

### Fuel Efficiency Improvements and Gas Consumption

Question:  Consider four cars, the first with a fuel efficiency of 5 miles per gallon, the second with a fuel efficiency of 10 miles per gallon, the third with a fuel efficiency of 20 miles per gallon, and the fourth with a fuel efficiency of 40 miles per gallon. How much gas does each car consume during a one thousand mile drive?   How much gas can be saved if a person uses a 10 mpg car rather than a 5 mpg car?  How much gas can be saved if a persons uses a 20 mpg car rather than a 10 mpg car?    How much gas can be saved by the use of a 40 mpg car rather than a 20 mpg car?

Answer:  Gas consumed is miles/ (miles/gallon)

At 5 mpg it takes 1000/5 or 200 gallons to make the trip.

At 10 mpg it takes 1000/10 or 100 gallons to make the trip.

At 20 mpg it takes 1000/20 or 50 gallons to make the trip.

At 40 mpg it takes 1000/40 or 25 gallons to make the trip.

The savings in fuel obtained by using a 10 mpg car rather than a 5 mpg car is 100 gallons. (200-100).

The savings in fuel obtained by using a 20 mpg care rather than a 10 mpg car is 50 gallons (100-50).

The savings in fuel obtained by using a 40 mpg car rather than a 20 mpg car is 25 gallons (50-25).