A supermarket is considering adding self-scan checkout machines. Currently the supermarket checks out 200 customers an hour using 10 checkout clerks. Customers differ in their abilities to use these machines. Market research suggests that 20 percent of the store's customers can check themselves out using these machines in three minutes (on average), 30 percent can check themselves out in five minutes, and 50 percent will refuse to use the new machines. One employee can monitor up to four self-scan machines. If there are fewer than four machines, this employee can use her extra time in other productive ways. Draw an isoquant for checking out 200 customers an hour where the variable inputs are checkout clerks and self-scan checkout machines.