Astudent is considering the purchase of two alternative cars. car a initially costs $1,500 more than car b, but uses 0.05 gallons per mile, versus 0.07 gallons per mile for car b. both cars will last for 10 years, and b's market value is $800 less than a's. fuel costs $4.00 per gallon. if all else equal, at how man miles driven per year does car a become preferable to car b?