The registration desk at the exclusive Le Meridien Hotel has four staff agents to check in the hotel guests. Guests arrive at the registration desk at an average rate of 40 per hour (Poisson distributed) and form a single line and wait for service from the next available agent. The average time for an agent to check in a guest is 5 minutes, and the service time has a negative exponential distribution. Each service agent is paid $15 an hour, and the cost of customer dissatisfaction and loss of good will as a result of excessive waiting times is $25 an hour. Determine how effective the present guest check-in system is at the hotel and whether an additional server (fifth service agent) is needed to improve service.