4. When Mercator Manufacturing Inc. checked its stores, it had the following inventory on hand as at December 31, 2015: (i) 5,000 litres of lubricating oil that had cost $2.50 per litre: As at December 31, the replacement price was $3.00 per litre. (ii) 50,000 kg of steel that had cost $0.50 per kg: As at December 31, the replacement price was $0.48 per kg. (iii) Spare parts that had cost $25,000: Mostly for production machinery that was no longer in use, so it was unlikely they could be used. They have no resale value. (iv) A replacement control unit for a customer's milling machine, which has a resale value of $10,000: The control unit was bought by the customer so that Mercator could use it to repair their milling machine. (v) $20,000 of electronic parts that were in good working order but had gone beyond their sell by dates on the packages. Required (a) Show how the inventory would appear in the balance sheet as at December 31, 2015. (b) If Mercartor Manufacturing's sales for 2015 totalled $500,000, calculate the following: The inventory turnover ratio The inventory holding period