A new shopping mall is considering setting up an information desk manned by one employee. Based on information

obtained from similar information desks, it is believed that people will arrive at the desk at the rate of 20 per hour. It

takes an average of 2 minutes to answer a question. It is assumed that arrivals are Poisson and answer times are

exponentially distributed.

Suppose that if an additional employee is hired, the cost of waiting time will be reduced to $6. In addition, the

cost of waiting time to receive service will be reduced by half. Should a new employee be hired? Show the new

total cost and justify.