Riverbed Inc. uses a periodic inventory system. Its records show the following for the month of May, in which 80 units were sold. Date Units Unit Cost Explanation Inventory Total Cost $ 248 May 1 31 $8 May 15 Purchase 23 9 207 May 24 Purchase 41 10 410 Total 95 $ 865 Calculate the cost of goods sold and the ending inventory at May 31 using the FIFO formula. Cost of goods sold $ Ending inventory $