to include lunch breaks for the doctors who staff the examination rooms. There are three doctors on duty for the f rst 3.5 hours of each 8-hour shift. For the next 90 minutes, the doctors take rotating 30-minute lunch breaks, resulting in only two doctors being available at any point during these 90 minutes. If all three doctors are busy with patients when the 90-minute lunch period begins, they wait until the f rst patient among the three is done, and that doctor takes the f rst 30-minute lunch break; each doctor gets a full 30-minute lunch, so if the 90-minute lunch period starts a little late, it also ends that much late. After all the lunch breaks end, all three doctors are available until the end of their 8-hour shift, at which point the second 8-hour shift begins with the same staff ng and lunch (maybe call it dinner) rules. Note that the 8 hours in a doctor’s shift include the 30-minute lunch break. Compare your results to those from Exercise