A car wash has a space that can only accommodate 3 cars and 2 lanes for washing cars. Each lane can only accommodate 1 car. Cars come to this place according to the Poisson process, at an average rate of 30 cars per hour, but avoid entering this place when it is full. This work and cleaning is done manually (by manpower), and appears to follow an exponential distribution Under normal circumstances, each lane takes an average of 5 minutes to service a car. However, if there are 2 cars waiting to be served, the service will be accelerated, thus shortening the average service time to 4 minutes. Determine (a) the number of cars expected to be in this car wash and (b) the time a car will spend in this place if it does not shy away from entering.