Problem 5-13 The manager of a car wash must decide whether to have one or two wash lines. One line will mean a fixed cost of $5,700 a month, and two lines will mean a fixed cost of $10.260 a month. Each line would be able to process 15 cars an hour Variable costs will be $3 per car, and revenue will be $5.95 per car. The manager projects an average demand of between 14 and 18 cars an hour. Would you recommend one or two lines? The car wash is open 300 hours a month. Choose (Click to select)y line