Question

Manual-transmission cars typically average 1-2 miles per gallon better than their automatic-transmission counterparts. Assume there are about 260 million cars in the U.S. and that 90% are automatics. (a) How much gasoline would we save each year if all drivers of automatics switched to comparable manual-transmission cars? Assume an average mileage of 25 mpg for manuals and 23 mpg for automatics.

Answer 1

On the average a car travels a distance of per year .

There are cars in U.S.

Number of automatic cars are

Number of manual cars are

Mileage of automatic car is   and mileage of manual car is

So the amount of usage of gasoline by an automatic car in one year is  

The amount of usage of gasoline by a manual car in one year is  

Total usage of gallons by automatic and manual cars is

If all the automatic cars are switched to manual cars, the usage of gasoline by all the manual cars is

Amount of gasoline save by swiching the automatic cars to manual cars is

that is million gallons can be saved.