Denna produces a machine that requires three pistons. They feel that they must prodace 200,000 machines next year. They want to hold, in their ending saterials inventory, enough pistons to meet 101 of next year production requirement. They will start the year with enough pistons to manufacture 15,000 machines. How many pistons must they purchase? 600.000 60.000 660,000 645.000 610.000