The queue lists 20 patient slots, but there are only 13 offices. The wait time is listed from 15 minutes to 2.5 hours, which is believed to be overstated. The expected wait time is the average in-line time divided by the patient arrival rate. If there is an average of 545 patients a day and the least productive workers show a service rate of about two patients an hour . You always use the least common denominator to understate the averages