Current Attempt in Progress Your answer is incorrect. Cullumber Company uses a periodic inventory system. Its records show the following for the month of May, in which 68 units were sold. Compute the ending inventory at May 31 and cost of goods sold using the FIFO, LIFO, and average-cost methods. (Round per unit cost to 3 decimal places, es. 15.647 and final answers to Odecimal places, eg. 5,125.)