Elon Musk of Tesla Motors Inc (NASDAQ:TSLA), SpaceX and SolarCity Corp (NASDAQ:SCTY) fame has advice for people who are seeking jobs. He says a big part of it is about the applicant’s problem-solving skills.

Elon Musk Tesla

Elon Musk on questioning job applicants

Speaking at Business Insider‘s Ignition conference earlier this year, Musk said one of the ways he determines if the person he is interviewing has the skills necessary for the job is by asking about the problems they have solved. He says when people struggle with problems, they truly understand it. On the other hand, people who were merely along for the ride in solving a problem won’t really be able to explain the solution.

“When I interview someone to work at the companies, I ask them to tell me about the problems they worked on and how they solved them,” Musk said. “And if someone was really the person that solved it, they’ be able to answer multiple levels. They’ll be able to go down to the brass tacks, and if they weren’t, they’ll get stuck.”

Musk says anyone who struggles with a problem never forgets it, and he alluded to his own problem-solving experience with Tesla Motors Inc (NASDAQ:TSLA) and SpaceX—two companies for which he has been solving problems for a decade or more.

Other interesting CEO interview questions

Business Insider also compiled a collection of some of the best and most interesting favorite questions posed by CEOs of various questions. My personal favorite was the question always asked by Capriotti’s Sandwich Shop CEO Ashley Morris, who asks every applicant: “What would you do in the event of a zombie apocalypse?”

Of course there were plenty of other more straight-laced questions on this other list, including some which were pretty similar to Musk’s question above, like Google Inc (NASDAQ:GOOG) senior VP Laszlo Bock, who asks: “Give me an example of a time when you solved an analytically difficult problem.”