A telephone call center uses three customer service representatives (CSRs) during the 8:30 to 9:00 a.m. time period. The standard service rate is 3.0 minutes per telephone call per CSR. Assuming a target labor utilization rate of 80 percent, how many calls can these three CSRs handle during this half-hour period?

Suppose an airport has a single runway, and planes arrive to land at the airport according to a Poisson process with an average rate of 10 planes per hour. The time it takes for a plane to land (including taxiing time) is exponentially distributed with a mean of 5 minutes. Additionally, there is a queue of planes waiting to land, and planes are served in a first-come-first-served (FCFS) manner.

(a)What is the expected number of planes in the queue?

(b)What is the expected waiting time for a plane in the queue?

(c)What is the probability that an arriving plane has to wait for landing?

(d)What is the probability that two planes are in the system?