Question: An auto dealership is running a promotional deal whereby they will replace your tires free of charge for the life of the vehicle when you purchase your car from them. You expect the original tires to last for 30,000 miles, and then they will need replacement every 30,000 miles thereafter. Your driving mileage averages 15,000 miles per year. A set of new tires costs $400. If you trade in the car at 150,000 miles with new tires then, what is the lump-sum present value of this deal if your personal interest rate is 12% per year?