258 PE 7-5B Periodic inventory using FIFO, LIFO, and weighted average cost methods OBJ. 4 The units of an item available for sale during the year were as follows: Jan. 1 Inventory 20 units at $360 $ 7,200 Aug. 13 Purchase 260 units at $342 88,920 Nov. 30 Purchase 40 units at $357 14,280 Available for sale 320 units $110,400 There are 57 units of the item in the physical inventory at December 31. The periodic in ventory system is used. Determine the inventory cost using (a) the first-in, first-out (FIFO) method; (b) the last-in, first-out (LIFO) method; and (c) the weighted average cost method