Periodic Inventory Using FIFO, LIFO, and Weighted Average Cost Methods The units of an item avallable 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 (a) the first-in, first-out (FIFO) method; (b) the last-in, first-out (LIFO) method; and (c) the weighted average cost method (round pen unit cost to two decimal places and your final answer to the nearest whole dollar)