The interview is ticking along nicely, then wham: your interviewer hits you with an unexpected and seemingly irrelevant problem-solving question.
So what to do when the focus suddenly switches from your skills and experience to being asked how many ping-pong balls there are in China?
First of all, don't panic, says Melissa Kuwahara, practice leader for the financial services team at CDS. You aren't expected to know the exact answer, the question is designed to test how well you think and articulate yourself under pressure.
"The key here is not to get stressed by it. The interviewers are not looking for the right answer, but rather your logic for getting to an answer, as well as your ability to remain calm, clear and to acknowledge and make assumptions as you go through the answer. They are also looking for creativity, so if you think of some assumptions that others didn't, that can be a positive," says Kuwahara.
Guy Howard, a manager at Hays Banking, says these types of questions are quite common in interviews. He thinks interviewers want to see how you handle being put under pressure, your thought processes, and how clearly you can explain your conclusion.
"The answer is almost irrelevant. You can give an answer that's completely wrong, but still come out well by showing your logic and explaining yourself clearly," he says.
And even if you do find yourself struggling, it's probably not the end of the world, says Kuwahara.
"This question is rarely a deal breaker for the interviewer and if you are not super innovative, just be calm, clear, logical and concise. Don't ramble and you will make it through," she adds.