"When hiring sales associates, employers are looking for charismatic candidates who can provide helpful advice to customers and close sales. Be prepared to answer a few scenario questions that will assess your ability to handle difficult customers, sell a product, or excel on a team. Previous sales experience is an advantage, but not necessary."
If you were busy with a line and checking out a customer and another customer seemed to need some help what would you do?
If there was another associate I'd point out that they needed help, or politely tell the customer I'd be with them in just a moment and apologize.