The following units of a particular item were available for sale during the calendar year: Jan. 1 Inventory 10,000 units at $75.00 Mar. 18 Sale 8,000 units May 2 Purchase 18,000 units at $77.50 Aug. 9 Sale 15,000 units Oct. 20 Purchase 7,000 units at $80.25 The firm uses the weighted average cost method with a perpetual inventory system. Determine the cost of merchandise sold for each sale and the inventory balance after each sale.