At Joe's Pool Hall They Rent Tables by the Hour

Essay

At Joe's Pool Hall they rent tables by the hour and also rent Balabushka pool cues for purists that can't afford their own. The rental process for these cues is exhaustive and takes an hour and a half for each application. There are three leasing agents that conduct these interviews, and on average, it is one hour between customer arrivals.
-What is the likelihood that there are three or fewer customers in the entire system? How does this compare with the likelihood of three or fewer customers in a system with the same arrival and service rates but staffed by four servers?