Average arrival rate of customers now has reached 20 per hour and Sunset Airlines must increase the capacity of its check -in system. Based on a customer survey, $15 per hour is considered the opportunity cost of waiting in queue. Clerks are paid $10 per hour and still process a passenger in three minutes. Evaluate the following check -in system alternatives to find the least expensive arrangement using total hourly costs of clerks and customers waiting in queue. First, consider a multiple queue configuration with two separate waiting lines and no customer jockeying. Assuming demand is equally divided between the two clerks, what is the total hourly cost of this arrangement?