Cullumber Marine Products began the year with 10 units of marine floats at a cost of $13.80 each. During the year, it made the following purchases: May 5,30 units at $20.20; July 16,15 units at $24.60; and December 7,20 units at $30.00. Assuming there are 25 units on hand at the end of the period, determine the cost of goods sold under (a) FIFO, (b) LIFO, and (c) average-cost. Cullumber uses the periodic approach