Periodic Inventory by Three Methods The units of an item available for sale during the year were as follows: Jan. 1 Inventory 1,020 units @ $124 Feb. 17 Purchase 1,395 units @ $126 Jul. 21 Purchase 1,640 units @ $128 Nov. 23 Purchase 1,140 units @ $128 There are 1,215 units of the item in the physical inventory at December 31. The periodic inventory system is used. not round intermediate calculation and round final answer to nearest whole value. a. Determine the inventory cost by the first-in, first-out method. b. Determine the inventory cost by the last-in, first-out method. c. Determine the inventory cost by the weighted average cost method