Raffles Ltds inventory records show the following information for the month of November. Raffles Ltd uses the perpetual inventory method. Date Details 1 Nov Beginning balance of 100 units @ $12,000 each 6 Nov Purchased 80 units @ $13,000 each 13 Nov Sold 120 units @ $20,000 each 20 Nov Purchased 150 units @15,000 each 28 Nov Sold 200 units @ $22,000 each. Required: Compute the cost of sales and gross profit using the a) First-in, First-out (FIFO) method (9 marks) b) Last-in, First-out (LIFO) method (9 marks)