Answer the questions in this problem using the queue network graph shown below. This is a Jackson network with six queue stations. Note: rates are in customers per hour.

Calculate the following average long$-$run performance metrics :

a$)$ Server utilization from station $4$

b$)$ The average time in the entire network

c$)$ The average number of customers waiting in the entire network

d$)$ The probability of zero customers in the system