Weighted Average Cost Method with Perpetual Inventory The beginning inventory at Midnight Supplies and data on purchases and sales for a three-month period ending March 31, are as follows: Number Date Transaction of Units Per Unit Total Jan. 1 Inventory 7,500 $75.00 $562,500 10 Purchase 22,500 85.00 1,912,500 28 Sale 11,250. 150.00 1,687,500 30 Sale 3,750 150.00 562,500 Feb. 5 Sale 1,500 150.00 225,000 10 Purchase 54,000 87.50 4,725,000 16 Sale 27,000 160.00 4,320,000 28 Sale 25,500 160.00 4,080,000 Mar. 5 Purchase 45,000 89.50 4,027,500 14 Sale 30,000 160.00 4,800,000 25 Purchase 7,500 90.00 675,000 30 Sale 26,250 160.00 4,200,000