Q. injection molding department of a company uses an average of 30 gallon of special lubricant a day. Supply of lubricant is replenished when amount on hand is 170 gallons. It takes four days for an order to be delivered. Safety stock is 50 gallon, which provides a stock-out risk of 9 percent. Illustrate what amount of safety stock would provide a stock-out risk of 3 percent? Assume normality.