The units of an item available for sale during the year were as follows: Jan. 1 Inventory 42 units at $60 Mar. 10 Purchase 58 units at $65 Aug. 30 Purchase 20 units at $68 Dec. 12 Purchase 30 units at $70 There are 36 units of the item in the physical inventory at December 31. The periodic inventory system is used. Requirements: 1. Determine the cost of merchandise available for sales 2. Determine the ending inventory cost and the cost of merchandise sold using method FIFO 3. Determine the ending inventory cost and the cost of merchandise sold using method average