Perpetual inventory using fifo the following units of a particular item were available for sale during the calendar year: jan. 1 inventory 4,000 units at $41 apr. 19 sale 2,500 units june 30 purchase 4,700 units at $44 sept. 2 sale 5,000 units nov. 15 purchase 1,900 units at $47 the firm maintains a perpetual inventory system. determine the cost of goods sold for each sale and the inventory balance after each sale, assuming the first-in, first-out method. present the data in the form illustrated in exhibit 3. under fifo, if units are in inventory at two different costs, enter the units with the lower unit cost first in the cost of goods sold unit cost column and in the inventory unit cost column.