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 90 miles per​ hour, and it can travel 105 miles per gallon of fuel. Another​ two-seater automobile costs ​$8,000 and averages 55 miles per gallon of compressed natural gas. If fuel costs ​$8.75 per gallon and MARR is 8​% per​ year, over what range of annual miles driven is the Dart more​ economical? Assume a useful life of seven years for both cars.