Ayayai Inc. uses a periodic inventory system. Its records show the following for the month of May, in which 79 units were sold. Date May 1 May 15 May 24 Explanation Inventory Purchase Purchase Total Units 31 26 42 99 Unit Cost $10 11 12 Total Cost $310 286 504 $1.100 (a) Calculate the cost of goods sold and the ending inventory at May 31 using the FIFO formula. $ Cost of goods sold Ending inventory $