A refueling station is served by a single pump machine for providing service to the petrol vehicles. The arrival process has shown that the distribution of times between arrivals is negative exponential with a mean of 10 minutes. Similarly, service times were found to be adequately described by a negative exponential distribution with a mean of 6 minutes. Waiting space is unlimited. Determine:
- Probability that the customer has to wait.
- Mean number of customer in the system.
- Percentage utilization of the service station.
- Steady-state probability of having four customers in the system.