Library Reference Desk. A single librarian is stationed at a reference desk of a university library that receives requests for assistance. Assume

that a Poisson probability distribution with an arrival rate of $10$ requests per hour can be used to describe the arrival pattern

and that service times follow an exponential probability distribution with a service rate of $12$ requests per hour. LO$2$ LO$2$ Solve for steady$-$state operating characteristics for a single$-$server waiting line with Poisson arrivals and exponential service

times.

What is the probability that no requests for assistance are in the system?

What is the average number of requests that will be waiting for service?

What is the average waiting time in minutes before service begins?

What is the average time at the reference desk in minutes $($waiting time plus service time$)?$

What is the probability that a new arrival has to wait for service?