Periodic inventory using FIFO, LIFO, and weighted average cost methods The units of an item avaliable for sale during the year were as follows: There are 75 units of the item in the physical inventoty 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 (LFO) method; and (c) weighted average cost method