Case - 4: Ibra Trader uses the perpetual inventory system. All sales returns from customers result in the goods being returned to inventory. Assume that there are no credit transactions and the inventory returned is not damaged. You are provided with the following information of the company for the month of April 2020. Quantity Cost per unit Selling price per unit Date Description (kg) (OMR) (OMR) Beginning inventory April 1 500 40 120 Purchase 40 2 Sale 450 ? 60 5 20 ? 6 Purchase return of 2nd dated purchase Sales return of 5th dated sale 30 ? 60 11 18 Sale 150 ? 60 Purchase 200 45 23 Sale 140 ? 60 28 Sale 80 ? 60 30 Question - 4: a. You are required to calculate units and cost of goods sold; units and cost of ending inventory; and gross profit for each of the following cost flow assumptions. i. LIFO, and (3.5 Marks) ii. WAM (3.5 Marks) b. Write any three control procedures to be followed over sales