Beginning inventory, purchases, and sales data for cellphones are as follows:

a. Assuming that the perpetual inventory system is used, costing by the FIFO method, determine the cost of goods sold for each sale and the inventory balance after each sale, presenting the data in the form illustrated in Exhibit 3, on page 310.
b. Assuming that the perpetual inventory system is used, costing by the weighted average method, determine the cost of goods sold for each sale and the inventory balance after each sale, presenting the data in the form illustrated in Exhibit 4, on page 311.

Inventory Purchases Sales Mar. 8 14 31 Mar. 1 1,000 units at $40 Mar. 5 500 units at $42 450 units at $44 700 units 600 units 300 units 20