Periodic Inventory by Three Methods The units of an item available for sale during the year were as follows: Jan. 1 Inventory 6 units @ $35 Feb. 17 Purchase 20 units @ $36 July 21 Purchase 9 units @ $39 Nov. 23 Purchase 9 units @ $40 There are 6 units of the item in the physical inventory at December 31. The periodic inventory system is used. a. Determine the inventory cost by the first-in, first-out method. $fill in the blank 1 b. Determine the inventory cost by the last-in, first-out method. $fill in the blank 2 c. Determine the inventory cost by the weighted average cost method. Round average unit cost to the nearest cent and final answers to the nearest whole dollar, if required. $fill in the blank 3