How do I get this answer

McCarthy Company has the following purchases and sales during the month of October. Using the FIFO perpetual inventory method, what amount will be reported as cost of goods sold for the 11 units that were sold? Date Units Sold at Retail October 1 October 2 October 4 Activities Beginning inventory Purchase Sales Units Acquired at Cost 8 units @ $200 = $1,600 20 units @ $205 = $4,100 11 units sold