11-21. An aerodynamic three-wheeled automobile

(the Dart) runs on compressed natural gas stored in two cylinders in the rear of the vehicle. The

$13,000 Dart can cruise at speeds up to 80 miles per hour, and it can travel 100 miles per gallon of fuel. Another two-seater automobile costs $10,000 and averages 50 miles per gallon of compressed natural gas. If fuel costs

$8.00 per gallon and MARR is 10% per year, over what range of annualmiles driven is the Dart more economical?

Assume a useful life of five years for both cars. (11.2)