Vaughn Co. uses a periodic inventory system. Its records show the following for the month of May, in which 73 units were sold. Compute the ending iriventory at May 31 and cost of goods sold using the FIFO and LFO methods. Vaughn Co. uses a periodic inventory system. Its records show the following for the month of May, in which 73 units were sold. Compute the ending iriventory at May 31 and cost of goods sold using the FIFO and LFO methods