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