It takes a highly intelligent person to land in front of Elon Musk for a job interview, and it takes an even bigger genius to pass his tests. When he was questioning engineers in the running for a SpaceX position, Musk needed a good question that would test the candidates’ logic skills, according to Ashlee Vance’s biography Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future. To see how their problem-solving skills fared, the CEO started asking a head-scratching brainteaser that would stump most people:
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?
In most parts of the planet, taking the south-west-north path would leave you a mile west of where you started, so you might have realized that the answer must be a place that doesn’t follow the same directional rules as the rest of the planet. In this case, it’s one of the Poles.
If you start at the North Pole and start by heading south, then west, then back north, you’ll end up walking in a triangle—right back to where you came. These are 19 more brainteasers that will leave you stumped.
OK, that wasn’t so tough. But just when you’re feeling smug about your answer, Musk has a follow-up question: Where else could you be?
This answer is more complicated, and it brings you to the opposite end of the globe, near the South Pole—specifically, one mile north of the line where Earth has a one-mile circumference. The person would walk south to hit that one-mile circumference area, travel in a complete circle while walking a mile west, then head back north to reach their starting position.
Did you get the right answer? Don’t feel too bad if you didn’t. Musk reportedly wasn’t so much looking for applicants with a solid sense of geography, but wanted a glimpse of how potential employees tackled unconventional questions. For more tough logic puzzles, see if you can solve 25 of the hardest riddles ever.