2. If you determined that a “fast checkout” line is not needed, Lesedi Baard is the general manager of Quickmart, a South African convenience store. Quickmart offer a basic selection of items including food and beverages, homecare, household products, apparel, and hardware. Their target market includes people who need only a few items and want to avoid going to a supermarket.

Its goal is to make each visit fast and efficient. For this reason, Lesedi installed four checkout counters in the store, and left room for a potential fifth one.

The peak hours are from 4:00 p.m. to 9:00 p.m., when people finish work and visit the store to buy a few necessities. During this time, all four checkout counters are open, with a separate line for each. Despite keeping all four checkout counters open, there is always a fairly long wait for customers, which causes some customers to not even enter the store, when they see the length of the lines. Since speed is the main concern for Lesedi, she is considering three possible plans to decrease the checkout time for customers.

The first option is to keep everything as is and install a fifth checkout counter and hire a new employee. The second option is to change the queuing system so there is only one line. The third option is to assign one of the checkout counters as a “fast checkout” counter, where people with 5 items or fewer can check out, and the other customers will form a single queue for the remaining 3 checkout counters.

Before deciding, Lesedi collects data for a three-week period.

She determines that on average 40 customers arrive every hour and it takes 4 minutes for a cashier to check out a customer.

Around 25% of total customers have 5 items or fewer and it takes a cashier 2 minutes to check them out. For customers with more than 5 items (75%), it takes a cashier 4.67 minutes to finish at the checkout counter