At Dr. Mark Stone's new brewery, it presently costs $50 to produce a keg of beer. He expects costs to decline by $2 a keg each year for the first 5 years as he and his brewery team learn how to run the brewery more efficiently. After 5 years the costs are expected to remain constant. Dr. Stone expects to produce 10,000 kegs of beer per year. What is the present value of the brewery's manufacturing costs for the first 10 years? Assume an interest rate of 6%