The next four questions are based on the following information. At a car wash station, on average, there are 4 cars coming in for the service every 10 minutes. The average wash time is 2 minutes. The Poisson distribution is appropriate for the arrival rate and service times are exponentially distributed. Please convert all rates into cars per hour and answer the following questions.
1: The average time a car spent in the waiting line is __________ hours, and the total time a car spent in this car wash station is _________ hour
2: What is the average number of cars in this car wash station is ___________
3: What is the probability that there are no cars in this station is _______________
4: What is the probability that there are exactly two cars in this station is __________