Topanga Group began operations early in 2018. Inventory purchase information for the quarter ended March 31, 2018, for Topanga's only product is provided below. The unit costs include the cost of freight. The company uses a periodic inventory system Unit Cost Date of Purchase Jan. 7 Feb. 16 March 22 Units 5,000 12,000 17,000 34,000 Total Cost $ 20,000 54,000 85,000 159,000 $4.00 4.50 5.00 Totals Sales for the quarter, all at $700 per unit, totaled 20,000 units leaving 14,000 units on hand at the end of the quarter Required 1. Calculate Topanga's cost of goods sold for the first quarter using a. FIFO b. LIFO c. Average cost 2. Calculate Toponga's gross profit ratio for the first quarter using FIFO, LIFO, and Average cost. 3. Comment on the relative effect of each of the three inventory methods on the gross profit ratio