How can I solve this problem? I'm trying to find the Value of Ending Inventory, Cost of goods sold, and Gross Profit of Sales using FIFO. Can I get an explanation of how?

Help on First-in, First-out Inventory Valuation - PERIODIC System Under the FIFO method of inventory valuation, it is assumed that the first units purchased (in) are the first units sold out): and the inventory on hand is from the last purchase(s). Beginning with the last purchase, add the total of the units purchased multiplied times the cost per unit until the total of the units purchased is equal to the physical count of the units of ending inventory. FIFO inventory is calculated the same way under both the Periodic system and the Perpetual system. If there are 300 units of ending inventory, and the last purchase was 800 units at $35 per unit, the value of the ending inventory under FIFO evaluation is $10.500 (= 300 x $35). Cost of Goods Sold = Beginning Inventory + Purchases - Ending Inventory Gross Profit on Sales = Sales - Cost of Goods Sold. First-In, First-Out Last-In, First-Out Selection: First-In, First-Out FIFO (First-in, First-out) Inventory Valuation PERIODIC System Activity Total Sales Unit Cost 17.00 Cost 34.00 Date Balance A. B 51.00 Units 2 -2 5 -4 10 15.00 Sale Purchase Sale Purchase 75.00 UA 102.00 19.00 190.00 Total 11 299.00 153.00 Value of Ending Inventory: Cost of Goods Sold: Gross Profit on Sales