Periodic Inventory by Three Methods The units of an item available for sale during the year were as follows: Jan. 1 Inventory 19 units at $47 Feb. 17 Purchase 20 units at $48 Jul. 21 Purchase 10 units at $50 Nov. 23 Purchase 4 units at $51 There are 11 units of the item in the physical inventory at December 31. The periodic inventory system is used. Round average unit cost to the nearest cent and finalwers to the nearest whole dollar if required. a. Determine the inventory cost by the first-in, first-out method. b. Determine the inventory cost by the lastin, first-out method. c. Determine the inventory cost by the weighted average cost method