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A mail order firm has a total of 12 Watts lines coming into the customer service department (CSD), which has five customer service representatives. On average, two potential customers call CSD every minute. Each customer service representative requires on average 2 minutes to serve a customer. On one of the days two of the Watts lines happen to be down (as a result only 10 Watts lines are available that day). Discuss the proportion of potential customers getting a busy signal, the average waiting time that customers experience, and the average utilization of customer service representatives.