a. Assuming that the perpetual inventory system is used, costing by the LIFO method, determine the cost of merchandise sold for each sale and the inventory balance after each sale, presenting the data in the form illustrated in Exhibit 4. Under LIFO, if units are in inventory at two different costs, enter the units with the HIGHER unit cost first in the Cost of Merchandise Sold Unit Cost column and LOWER unit cost first in the Inventory Unit Cost column. Schedule of Cost of Merchandise Sold LIFO Method Prepaid Cell Phones Perpetual Inventory Using LIFO Beginning inventory, purchases, and sales data for prepaid cell phones for May are as follows: Inventory May 1 1,200 units at $31 Purchases May 10 Sales 20 600 units at $33 540 units at $35 May 12 840 units 14 720 units 31 360 units Cost of Cost of Quantity Purchases Purchases Quantity Unit Cost Total Cost Merchandise Merchandise Sold Sold Unit Cost Total Cost Sold Inventory Inventory Inventory Quantity Unit Cost Total Cost Date Purchased May 1 May 10 May 12 May 14 May 20 May 31 May 31 Balances