Trucks arrive at the loading dock of a wholesale grocer at an average rate of 1.2 per hour in the mornings. A single crew consisting of two workers can load a truck in about 30 minutes. Crew members receive$10 per hour in wage and fringe benefits, and trucks and drivers reflect an hourly cost of $60. The manager is thinking of adding another member to the crew. The average service rate would then be 2.4 trucks per hour. Assume both arrival and service rates are Poisson.
a. Would tire third crew member be economical?
b. Would a fourth member be justifiable if the resulting average service capacity were 2.6 trucks per hour?