The following information is available for Massey Company: Beginning inventory 600 units at $5 First purchase 900 units at $6 Second purchase 500 units at $7 Assume that Massey uses a periodic inventory system and that there are 800 units left at the end of the month. Instructions Show your work and Compute each of the following under the average-cost method: (a) Cost of ending inventory. (b) Cost of goods sold.