Periodic inventory using FIFO, LIFO, and weighted average cost methods The units of an item available for sale during the year were as follows: There are 75 units of the item in the physical inventory at December 31 . The periodic inventory system is used. Determine the inventory cost using the (a) first-in, first-out (FIFO) method; (b) last-in, first-out (LIFO) method; and (c) weighted average cost method