Mike manages a theater complex called Cinema I, II, III and IV.  Each of the four auditoriums plays a different film; the starting times are staggered to avoid the large crowds.  The Cinema has one ticket booth and a cashier who can maintain an average service rate of 280 patrons per hour.  Service times are assumed to follow an exponential distribution.  Arrivals on a typical activity day are Poisson distributed and average 210 per hour.   

To determine the efficiency of the current ticket operation, Mike wishes to examine several queue operating characteristics.

What is the probability that there are more than two people in the system?

1. More than three? 

2. More than four?