Periodic Inventory Using FIFO, LIFO, and Weighted Average Cost Method. The units of an item available for sale during the year were as follows: Jan. 1 Inventory 7 units at $36 $252 Aug. 13 Purchase 16 units at $38 608 Nov. 30 Purchase 10 units at $39 390 Available for sale 33 units $1,250 There are 20 units of the item in the physical inventory at December 31. The periodic inventory system out (FIFO) method; (b) the last-in, first-out (LIFO) method; and (c) the weighted average cost method to the nearest whole dollar). a. First-in, first-out (FIFO) b. Last-in, first-out (LIFO) c. Weighted average cost