Below is the picture of the problem. I don't understand the FIFO and LIFO info and how I get that or how I get the avg cost.

Required information [The following information applies to the questions displayed below.] Warnerwoods Company uses a perpetual inventory system. It entered into the following purchases and sales transactions for March. Date Activities Units Acquired at Cost Units Sold at Retail Mar . 1 Beginning inventory 120 units @ $51.40 per unit Mar . Purchase 235 units @ $56.40 per unit Mar . 9 Sales 280 units @ $86.40 per unit Mar. 18 Purchase 95 units @ $61.40 per unit Mar. 25 Purchase 170 units @ $63.40 per unit Mar. 29 Sales 150 units @ $96.40 per unit Totals 620 units 430 units 4. Compute gross profit earned by the company for each of the four costing methods. For specific identification, the March 9 sale consisted of 75 units from beginning inventory and 205 units from the March 5 purchase; the March 29 sale consisted of 55 units from the March 18 purchase and 95 units from the March 25 purchase. (Round weighted average cost per unit to two decimals and final answers to nearest whole dollar.) Gross Margin FIFO LIFO Avg. Cost Spec. ID Sales Less: Cost of goods sold Gross profit