Arizona State University

CIS 309

1) Decreasing the activity time of any activity in a business process always improves the flow time. True 2) To maximize profits, it is always better to give priority to produce products (or provide services) with the highest unit contribution margins (defined as product's revenue minus all of its variable costs). False 3) On average, 30 cars enter the car wash per hour and are served at that rate. On average, a car waits 12 minutes in queue to be served. On average, how many cars wait in queue? (Hint: Use Little's Law) Throughput R = 30 per hour, Waiting time in queue T = 12 minutes = 0.2 hours. Inventory I = RxT = 6 4) On average, 30 patients arrive and are processed per hour at an emergency room. First, patients wait in queue for registration. After that, patients wait to be seen by a doctor. On average, there are 20 patients waiting for registration and another 40 waiting to be seen by a doctor. On average, how many hours does a patient wait in the ER (just waiting time, not including registration time) before being seen by a doctor? (Hint: Use Little's Law) Given, throughput = 30 patients/hr Avg inventory=20+40=60 patients Average flow time(T)= avg. inventory(I)/ throughput(R), 60/30 =2hrs