Even if you’re not interested in working for Tesla or SpaceX, CEO Elon Musk’s favorite interview question is an important one to think about. If you come up with a good answer, it could help you land your next gig at wherever you want to work.

Back in 2017, Musk told the World Government Summit that he asked every candidate: 

“Tell me about some of the most difficult problems you worked on and how you solved them.”

Musk interviews quite a few engineers for both Tesla and SpaceX, so the question makes sense: He wants to see how they worked through a thorny issue, step by step. “The people who really solved the problem, they know exactly how they solved it, they know the little details,” he added at the time.  

According to a recent column in Inc., there’s sound scientific reasoning behind Musk’s question: Those who actually know what they’re talking about are inclined to go into detail (exhaustive detail, sometimes), while those who have to rely on BS will often gloss over the finer points (which they don’t know).  

Wherever you’re interviewing, and for whatever type of job, one thing should be clear: providing as much detail as possible can only help you, whether you’re dealing with a recruiter during the initial stages or you’re in the final round with the hiring manager. Most of all, you’ll want to leverage all that detail to show how you added value to your previous companies, overcame incredible challenges, and/or ultimately left a project better than you found it. 

At the same time, you must also explain (in detail) how you’ll use all that experience and expertise in order to help your prospective employer achieve its goals. That requires doing your research about the company, position, and the skills they’re looking for. Remember, one of the biggest ways that technologists flub interviews is through failing to understand the hiring manager’s needs and pain points. 

Before heading into the interview, make sure to review a few relevant stories from your professional background. If you can, ask a friend or trusted colleague to hear you out; they can tell you if you’re skimping on necessary detail. If you know ahead of time that the interview will involve a whiteboard or keyboard test, run through a few sample coding problems to get into the right mindset. 

Back to Musk for a moment: That’s not the only question he’s infamous for asking potential employees. Back in 2015, technology journalist Ashlee Vance’s excellent biography of the CEO revealed that he asked prospective SpaceX engineers a particularly perplexing riddle:

“You’re standing on the surface of the Earth. You walk one mile south, one mile west, and one mile north. You end up exactly where you started. Where are you?”

The easy answer: the North Pole. However, as you can tell from the comments when we posted the question on Dice, there are lots of creative responses (“still on Earth,” “anywhere with a broken compass,” and so on). It’s not clear whether Musk still asks candidates that question, but landing a job at SpaceX requires running a whole battery of interviews designed to test your skills and knowledge. After all, you’re helping build, launch, and return rockets to Earth—you really have to know your stuff.