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 Date Quantity Cost per unit Selling price per unit Description (kg) (OMR) (OMR) April 1 Beginning inventory 2 Purchase 400 5 Purchase return of 2nd dated purchase Purchase 240 800 10 12 40 ? 12 6 Sale 11 1,000 ? 18 Sale 300 20 18 ? 13 100 Purchase 23 160 Sale ? 22 28 30 Sales return of 28th dated sale 10 ? 22 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. FIFO, and (3.5 Marks) ii. LIFO. (3.5 Marks) b. Write any three control procedures to be followed over purchase