Montoure Company uses a perpetual inventory system. It entered into the following calendar-year purchases and sales transactions Activities Units Sold at Retail Units Acquired at Cost 660 units $55 per unit 330 units $52 per unit 110 units $40 per unit Jan. 1 Beginning inventor;y Feb. 10 Purchase Mar. 13 Purchase Mar. 15 Sales Aug. 21 Purchase Sept. 5 Purchase Sept. 10 Sales 780 units $75 per unit 140 units$60 per unit 420 units $56 per unit 560 units $75 per unit 1,340 units Totals 1,660 units