EX 6-12 Periodic inventory by three methods Obj, 2, 4 The units of an item available for sale during the year were as follows: There are 1,500 units of the item in the physical inventory at December 31. The periodic inventory system is used. Determine the inventory cost by the (a) first-in, first-out method, (b) last-in, first-out method, and (c) weighted average cost method