An engineer has been set the objective of improving the process at a machine served by a FIFO queue, with the following objectives: $1.$ Ensure that the percentage of time that there are more than two jobs in the system $($machine $+$ queue$)$ is less than $25\%2.$ Ensure that no more than $5\%$ of jobs will experience more than $5$ minutes of queuing time while waiting for service on the machine. She has studied the existing system and determined that the jobs arrive in the queue at a rate of $20$ jobs per hour. She has also shown that the time between arrivals is exponentially distributed. She has determined a series of improvements to the existing process that will result in an exponentially distributed service time of $1\mathrm{.}5$ minutes.