I need every detail possible about the processes please

5. Customers arrive at the cash register of a small business according to a Poisson distribution with a rate of 25 customers per hour. The time of service at the cash register (payment + packaging) follows an exponential distribution with a mean of 4 minutes. Generally, there is a single employee attending at the cash register, however, when there are four or more customers in line, the cashier gets some help from a "Packer" which reduces the average service to 2.5 minutes. On the other hand, arriving customers who observed 10 customers (or more) in line leave the business and do not return. Calculate: The expected number of customers in line. b. The expected time in the system. The proportion of time that the cashier is idle. d. The expected number of customers that are lost. a. C