Imagine you have some workers and some handheld computers that you can use to take inventory at a warehouse. There are diminishing returns to taking inventory. If one worker uses one computer, he can inventory 125 items per hour. Two workers sharing a computer can together inventory 175 items per hour. Three workers sharing a computer can together inventory 185 items per hour. And four or more workers sharing a computer can together inventory fewer than 185 items per hour. Computers cost $100 each and you must pay each worker $25 per hour.