Houston Home Supplies (HHS) uses the periodic inventory system. At the beginning of 2020, they had 9,000 units of inventory with a total cost of $90,000. At the end of the year, there were 10,000 units on hand according to the physical count. During the year, they made the following purchases: March 26 June 12 15,000 units 30,000 units $180,000 420,000 Required a) How many units did HHS sell during the year? The sale price remained consistent, at $33 per unit Calculate the sales revenue for the year. SHOW WORK! (4 marks) b) Calculate the cost of goods sold and ending inventory values using the weighted average cost method. What is the gross margin for the year? (6 marks)