Please provide solution, formula, and calculation *** The service department of a car dealership works 200 days a year and uses 200 gallons of oil per day. The cost of placing an order s $40, and the annual inventory holding cost is 20% of the unit price. The service manager just received the unit prices for different quantity levels of order. Quantity (gallons) Price 1-1,499 $2.50 per gallon 1,500 - 2,999 $2.2 per gallon 3,000 - 4,999 $2.00 per gallon 5,000 or more $1.50 per gallon a. Compute the optimal order quantity? b. At the optimum order quantity, compute the total inventory cost, including the cost of buying the material, ordering, and holding cost