Can you solve Elone Musk Favorite Riddle?
Elon Musk is known as the co-founder of PayPal and Tesla Motors. He’s often called the real life version of the comic book character “Iron Man.” A new authorized biography of him, Elone Musk is already listed as a best-seller on Amazon in pre-sales.
Answer by and quora user Jim Davis
You can be any number of places close to the South Pole; as long as it’s more than a mile out and results in you traversing a one mile circumference of the globe at that point.
If you’re a mile North of the South Pole, then walk one mile South, you’re now at the South Pole and therefore can’t walk one mile West like the question states. You’d have to be the exact distance from the South Pole that creates a circumference of exactly one East/West mile once you’ve traveled one mile South. That way you start at Point A, travel one mile South to Point B, travel one mile West (or East) to completely circle the globe and end up back at point B, then travel one mile North and end up back at Point A.
Here’s my little 30 second AutoCAD sketch to help demonstrate. Forgive the crudity and the complete lack of scale.
You can see that anywhere along the Cyan line is an acceptable location to make all the parameters possible. This is why there are many locations close to the South Pole that are possible and only one at the North Pole.
The reason there is only one location at the North Pole is that you’re starting off traveling South one mile. This gives you a minimum approximated radius of one mile to the portion of the sphere you’re standing on. This means that the circumference where you’re now standing is at least 2π miles; which means you won’t end up in the same place after traveling 1 mile West as you would near the South Pole. (I know I’m grossly oversimplifying spherical geometry but it works for the purposes of this explanation. The concept is still there.) But that’s okay, because once you DO travel that 1 mile West, and then that 1 Mile North, you end up at the North Pole again; as long as that’s where you started.