Periodic Inventory Using FIFO, UFO, and Weighted Average Cost Methods The units of an item available for sale during the year were as follows: There are 20 units of the item in the physical inventory at December 31. The periodic inventory system is used. Determine the inventory cost using the first-in, first-out (FIFO) method; the last-in, first-out (LIFO) method; and the weighted average cost method (round per unit cost to two decimal places and your final answer to the nearest whole dollar). a. First-in, first-out (FIFO) $ b. Last-in, first-out (LIFO) $ c. Weighted average cost $