Sheffield Inc. uses a perpetual inventory system. Its records show the following for the month of May. Unit Total Date Explanation Units Cost Cost May 1 Inventory 29 $7 $203 May 15 Purchase 26 8 208 May 18 Sale (44) May 24 Purchase 41 9 369 Total 52 $780 52 (b) Calculate the cost of goods sold for May and the ending inventory at May 31 using the average cost formula. (For average, use 3 decimal places, e.g. 15.235 in your calculations and round final answers to 2 decimal places, e.g 5.25.) Cost of goods sold $ Ending Inventory $