Mar. 1 beginning inventory 100 units @ $50.00 per unit mar. 5 purchase 400 units @ $55.00 per unit mar. 9 sales 420 units @ $85.00 per unit mar. 18 purchase 120 units @ $60.00 per unit mar. 25 purchase 200 units @ $62.00 per unit mar. 29 sales 160 units @ $95.00 per unit totals 820 units 580 units problem 5-1a part 4 4. compute gross profit earned by the company for each of the four costing methods. for specific identification, the march 9 sale consisted of 80 units from beginning inventory and 340 units from the march 5 purchase; the march 29 sale consisted of 40 units from the march 18 purchase and 120 units from the march 25 purchase. (round weighted average cost per unit to two decimals.)