Could you explain the reasoning/math also?

Inventory Costing Methods-Periodic Method The Lippert Company uses the periodic inventory system. The following July data are for an item in Lippert's inventory: July 1 Beginning inventory 35 units 10 Purchased $13 per unit $14 per unit S5 units 65 units 15 Sold 26 Purchased $15 per unit 30 units Calculate the cost of goods sold for July and ending inventory at July 31 using (a) first-in, first-out, (b) last-in, first-out, and (c) the weighted-average cost methods. Round your final answers too the nearest dollar. A First-in, First-out: Ending Inventory Cost of Goods Sold: B. Last-in, first-out Ending Inventory Cost of Goods Sold: C. Weighted-average cost: Ending Inventary Cost of Goods Sold