Harper Co. reported the following current-year purchases and sales for its only product. Harper uses a perpetual inventory system. Determine the costs assigned to ending inventory and to cost of goods sold using (a) FIFO and (b) LIFO. Compute the gross margin for each method. Assume that ending inventory is made up of 5 units from the March 14 purchase, 15 units from the July 30 purchase, and the units of the October 26 purchase. Using the specific identification method, calculate (a) the cost of goods sild and (b) the gross profit. Harper Co. reported the following current-year purchases and sales for its only product. Harper uses a perpetual inventory system. Determine the costs assigned to ending inventory and to cost of goods sold using (a) FIFO and (b) LIFO. Compute the gross margin for each method. Assume that ending inventory is made up of 5 units from the March 14 purchase, 15 units from the July 30 purchase, and the units of the October 26 purchase. Using the specific identification method, calculate (a) the cost of goods sild and (b) the gross profit