You are serving as the only cashier at a supermarket. But there's no queue: instead, after you finish processing a customer, you decide which customer to process next. Every minute, a customer arrives at your checkout: 10% of the time, they have a big basket, which takes 5 minutes to process. Otherwise, they have a small basket, which takes 30 seconds to process. Can you come up with a strategy that processes customers both efficiently and fairly? Feel free to create and solve your own extensions and variants!