Lime company purchased 200 units for $30 each on January 31. It purchased 200 units for $40 each on February 28. It sold a total of 270 units for $100 each from March 1 through December 31. If the company uses the last-in. first-out inventory costing method, calculate the cost of ending inventory on December 31. (Assume that the company uses a perpetual inventory system.)