a. Roselle TVs uses a perpetual inventory system. For its flat-screen television sets, the January 1 inventory was 3 sets at 600 each. On January 10, Roselle purchased 6 units at 607 each. The company sold 2 units for $800 each on January 8 and 4 units for $820 each on January 15. Compute the ending inventory, cost of goods sold, and gross profit under (1) FIFO (2) moving-average cost. b. What is the advantages and disadvantages of perpetual inventory system