5-9. A new six-speed automatic transmission
for automobiles offers an estimated 4% improvement
in fuel economy compared to traditional fourspeed
transmissions in front-wheel drive cars. If a
four-speed transmission car averages 30 miles per
gallon and gasoline costs $4.00 per gallon, how much
extra can a motorist pay for a fuel-efficient six-speed
transmission? Assume that the car will be driven for
120,000 miles over its lifetime of 10 years. The motorist
can earn 6% per year on investments. (5.3)