An automobile tier II supplier has been offered a contract to supply a gearbox to a car company. The initial price of the gearbox is $389, and the car company is ready to give a contract to the supplier to supply 500,000 gearboxes in the first year, increasing by 2% every year, if the supplier is ready to bring down the price of the gearbox every year by $7.50 over the 12-year life of the contract. How much is the contract worth to the supplier at 6% interest? Please do in excel if possible and explain functions used.