Putra Automation Inc. is considering setting up a technical desk in the production line manned by one employee. Based on the information obtained from the production line, it is believed that people will arrive at the technical desk at a rate of 15 per hour. It takes an average of 3 minutes to answer technical question. It is assumed that the arrivals follow a Poisson distribution and answer times are exponentially distributed. Assume that the technical desk employee get a salary of Rp 50,000.- per hour. The cost of waiting time in the line or queue, in terms of customer unhappiness with the company, is Rp 75,000.- per hour of time spent waiting in line.

(a)Calculate the average number of people waiting in this system.

(b)Determine the average number of people waiting in this queue.

(c)Calculate the expected time for a person spends waiting in this system.