I need help ASAP

Sandy's Discount Computer Outlet just opened and uses the Perpetual Inventory system. She purchased 8 identical laptops from Dell. All of them had the same features and model number in addition to being the same size. The laptops do not have serial numbers on them. She purchased two on May 10th and paid $800 each She purchased one on May 16th and paid $840 She purchased two on May 20th and paid $720 each She purchased three on May 28th and paid $780 each (ilf Sandy uses the FIFO Method of costing inventory, what is the total COGS (Cost of Goods Sold) amount for May if she sells five laptops during the month? (ii) What is her ending Inventory dollar amount at the end of May if she sells five computers during the month? (iii) If the selling price of each laptop is $1,300, what is her Gross Margin/Gross Profit and Gross Margin/Profit % in May, assuming five laptops are sold? (iv) Could the Business have used the Specific Cost Method it it wanted to? Why or why not