need help with d-f

please note there is an error in the printing, The arrival rate should be , not , and the service rate should be , not .

thank you :-)

Alpha Walk-in Clinic operates as a single channel single server system. On Tuesdays, its average arrival rate () per hour is 7.0. Analysis indicates that its service rate () is 8.5 patients per hour. Using queuing theory, describe this service system. What is: d. The average number of patients in the queue waiting for service? e. The average time (hours) a patient spends in the queue waiting? f. The probability that the patient, upon arrival, must wait