Weighted average cost flow method under perpetual inventory system The following units of a particular item were available for sale during the calendar year: Date Line Item Description Units and Cost Jan. 1 Inventory 9,000 units at $50.00 Mar. 18 Sale 7,000 units May 2 Purchase 8,000 units at $56.50 Aug. 9 Sale 8,000 units Oct. 20 Purchase 4,000 units at $60.00 The firm uses the weighted average cost method with a perpetual inventory system. Determine the cost of goods sold for each sale and the inventory