OfficeSupplies Inc. uses a periodic inventory system. It entered into the following purchases and sales transactions for June.

Date	Activities	Units Acquired at Cost	Units Sold at Retail
Jun. 1	Beginning inventory	200 units @ $40 per unit
Jun. 7	Purchase	400 units @ $45 per unit
Jun. 14	Sales		350 units @ $70 per unit
Jun. 20	Purchase	350 units @ $50 per unit
Jun. 28	Sales		300 units @ $80 per unit

For specific identification, the June 14 sale consisted of 50 units from beginning inventory and 300 units from the June 7 purchase; the June 28 sale consisted of 200 units from the June 20 purchase and 100 units from the June 7 purchase.

Required:

1. Compute the cost of goods sold and ending inventory using FIFO and LIFO methods.
2. Determine the weighted average cost per unit and the ending inventory value.
3. Analyze the effect of inventory costing methods on key financial ratios, such as return on assets and inventory turnover.
4. Discuss the strategic implications of inventory management for OfficeSupplies Inc. and recommend an optimal inventory costing method.