22. The injection molding department of a company uses an average of 30 gallons of special lubri- cant a day. The supply of the lubricant is replenished when the amount on hand is 170 gallons. It takes four days for an order to be delivered. Safety stock is 50 gallons, which provides a stock- out risk of 9 percent. What amount of safety stock would provide a stockout risk of 3 percent? Assume normality.