Her business model
Kate manages an express M&S store. It is a small grocery store for quick, basic shopping (lunch sandwich, smoothie, basic home things, etc.). The store has three cash desks. All of them are open during rush hours and are very crowded.
Solution for Kate
Kate’s choice - LIVE queue set. All of the cash desks are offering the same service, so we organize one live queue for all of the free. In this case, the waiting is fair for each customer. When a cash desk is free, the next customer is called to come to that desk.