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