Please explain the math required

The following information relates to Toolworks Ltd.'s inventory transactions during the month of October. All of the units sold on October 5 were priced at $25.00 per unit. All of the units sold on October 15 and 31 were priced at $38.00 per unit. (a1) Toolworks Ltd. uses the periodic inventory system. Calculate Toolworks' cost of goods sold, gross margin, and ending inventory for the month of October using FIFO. Cost of Goods Sold $ Gross Margin $ Ending Inventory \$ $ Toolworks Ltd. uses the periodic inventory system. Calculate Toolworks' cost of goods sold, gross margin, and ending inventory for the month of October weighted-average. (Round calculations for cost per unit to 2 decimal places, e.g. 10.52 and final answers to 2 decimal places, e.g. 610.52.) Cost of Goods Sold $ Gross Margin $ Ending Inventory $ (b) Which of the cost formulas would produce the higher gross margin? The method results in the higher gross margin