Perpetual inventory using LIFO Beginning inventory, purchases, and sales data for DVD players are as follows: The business maintains a perpetual inventory system, costing by the last-in, first-out method. Determine the cost of goods sold for each sale and the inventory balance atter each sale, presenting the data in the form illustrated in Exhibit 4 . Under UFO, if units are in inventory at two different costs, enter the units with the HIGHER unit cost first in the Cost of Goods Sold Unit Cost column and LOWER unit cost first in the Inventory Unit cost column