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The Brainteaser Elon Musk Asks New SpaceX Engineers
Nerval's Lobster writes: The latest biography of Elon Musk, by technology journalist Ashlee Vance, provides an in-depth look into how the entrepreneur and tech titan built Tesla Motors and SpaceX from the ground up. For developers and engineers, getting a job at SpaceX is difficult, with a long interviewing/testing process... and for some candidates, there's a rather unique final step: an interview with Musk himself. During that interview, Musk reportedly likes to ask candidates a particular brainteaser: "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?" If you can answer that riddle successfully, and pass all of SpaceX's other stringent tests, you may have a shot at launching rockets into orbit.
You all fail.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
When you walk the mile south you reach the South Pole. How do you go "west". From the South Pole every direction is north.
"In America, first you get the sugar, then you get the power, then you get the women..." -H. Simpson
You'd only be partially correct.
There are actually multiple solutions:
1.) North Pole (one mile south, one west, and one north brings you back to the north pole)
2.) A ring of points approximately 2 miles just north of the the south pole, such that when you walk one mile south, you're even closer to the pole, then walk one mile west, going completely "around the world", back to where you started your westward travel, and one mile north, bringing you back to your original position.
The north pole and a circle of lat 1 + 1 / (2 * PI) north of the south pole. The distance is an approximation but is 'close enough for rocket science'. When you walk east you circumnavigate.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
The question says "one mile south, one mile west, and one mile north." The west-bound portion is a curved line. If you walk a straight line, after one step you are no longer walking west, but rather a south-of-west direction.
Nope, those rings are all more than a mile north of the south pole, so there is plenty of room to walk a mile south. The second ring has you walk south to a point close enough to the south pole that your mile west goes around twice, but you start a mile north of the point you can circumnavigate twice.