An office employs several clerks who create documents and has one operator who enters the document information in a computer

system. The group creates documents at a rate of $25$ per hour. The operator can enter the information with an average exponentially

distributed time of two minutes. Assume the population is infinite, arrivals are Poisson, and queue length is infinite with FCFS

discipline.

a$.$ Calculate the percentage utilization of the operator.

Note: Round your answer to $1$ decimal place.

Utilization of the operator

$\%$

b$.$ Calculate the average number of documents in the system.

Average number of documents

c$.$ Calculate the average time in the system.

Average time in the system

minutes

d$.$ Calculate the probability of four or more documents being in the system.

Note: Round your intermediate calculations to $3$ decimal places and final answer to $1$ decimal place.