Impossible Riddle – One Mile South, One Mile West, One Mile North



I’m somewhere on earth. I walk one mile south, one mile west, and one mile north. I end up exactly where I started. Where am I?

This puzzle is a classic brain teaser that was asked at Microsoft. It is also one of the favorites of Elon Musk, co-founder of PayPal and Tesla Motors.

This problem appears in my book Math Puzzles Volume 1 (nearly 5 stars on 9 ratings) which contains many interesting brain teasers and math riddles: http://amzn.to/1GhUUSH

See the solution in a blog post – http://mindyourdecisions.com/blog/2015/05/15/mashable-is-wrong-heres-the-complete-solution-to-elon-musks-favorite-interview-riddle/

If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecisions

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h/t: http://mashable.com/2015/05/13/elon-musk-job-interview/

I learned about this puzzle from William Poundstone’s book “How Would You Move Mount Fuji” which is a collection of many interesting puzzles that were asked at Microsoft. http://amzn.to/1FnSpml

My Books

“The Joy of Game Theory” shows how you can use math to out-think your competition. (rated 4/5 stars on 23 reviews) https://www.amazon.com/gp/product/1500497444

“The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias” is a handbook that explains the many ways we are biased about decision-making and offers techniques to make smart decisions. (rated 5/5 stars on 1 review) https://www.amazon.com/gp/product/1523231467/

“Math Puzzles Volume 1” features classic brain teasers and riddles with complete solutions for problems in counting, geometry, probability, and game theory. Volume 1 is rated 4.5/5 stars on 11 reviews. https://www.amazon.com/gp/product/1517421624/

“Math Puzzles Volume 2” is a sequel book with more great problems. https://www.amazon.com/gp/product/1517531624/

“Math Puzzles Volume 3” is the third in the series. https://www.amazon.com/gp/product/1517596351/

“40 Paradoxes in Logic, Probability, and Game Theory” contains thought-provoking and counter-intuitive results. (rated 4.9/5 stars on 7 reviews) https://www.amazon.com/gp/product/1517319307/

“The Best Mental Math Tricks” teaches how you can look like a math genius by solving problems in your head (rated 4.7/5 stars on 3 reviews) https://www.amazon.com/gp/product/150779651X/

“Multiply Numbers By Drawing Lines” This book is a reference guide for my video that has over 1 million views on a geometric method to multiply numbers. (rated 5/5 stars on 1 review) https://www.amazon.com/gp/product/1500866148/

source

Fahad Hameed

Fahad Hashmi is one of the known Software Engineer and blogger likes to blog about design resources. He is passionate about collecting the awe-inspiring design tools, to help designers.He blogs only for Designers & Photographers.

35 thoughts on “Impossible Riddle – One Mile South, One Mile West, One Mile North

  • September 26, 2017 at 12:23 am
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    I found a cheeky answer to this riddle. How about just say that my starting point is one mile west. Starting there I walk down one mile south, left one mile west and up one mile north. I end up exactly where I started. One mile west.

    Reply
  • September 26, 2017 at 12:23 am
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    6:39 You could also be at the gym, having walked a mile apiece on three separate treadmills facing three separate directions.

    Reply
  • September 26, 2017 at 12:23 am
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    when he asks where am i?
    me "somewhere that measures with imperial measurements, duh.(stupid americans)"

    Reply
  • September 26, 2017 at 12:23 am
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    Like the man who bought a cabin 3walls have a widow and 1 wall has a door , all his windows face north as he's standing at his door a bear walks past. the question is what colour was the bear……

    Reply
  • September 26, 2017 at 12:23 am
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    Start 1 mile from the South Pole. Go 1 mile south and you'll end up at the South Pole. Go west 1 mile and you'll end up on the same point due to it being infinitely small. Go one mile north and your at the starting point.

    Reply
  • September 26, 2017 at 12:23 am
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    Where are you? Well, isn't it obvious? You're exactly back where you started. 😒 Whereas I, I ended up in front of the fridge! 😲

    Reply
  • September 26, 2017 at 12:23 am
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    Have another answer that works. Your in your shoes! No matter where you walk, you started and ended in your shoes.

    Reply
  • September 26, 2017 at 12:23 am
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    I don't believe it. Someone in the northern hemisphere prove it with a video. Walk exactly 1 mile east or west, then one mile north, then one mile south. I think no one will be able to prove this, and they won't be right back where they started.

    Reply
  • September 26, 2017 at 12:23 am
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    Let's all join together and test these. Standing at and spinning around the south pole will be something worth doing in order to test the really small circles ;).

    Reply
  • September 26, 2017 at 12:23 am
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    if you walk really slowly you can wait for whereever you are to orbit back to where you started in a year or way more considering the tilt of the earth

    Reply
  • September 26, 2017 at 12:23 am
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    Those lines aren't going in the direction they are supposed to. They were curved.

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  • September 26, 2017 at 12:23 am
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    I immediately new it was the north pole. It's pretty obvious, since at the north pole, there is no "east" or "west", therefore, you can go south as far as you want, go west, or even east, as far as you want, but if you go north, no matter where you are on Earth, as long as you go north, the same distance as you go south from the start, if you end up at the same place, you will always be on the north pole.

    Reply
  • September 26, 2017 at 12:23 am
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    So to be a nitpicker, the answer is only sort of infinity time infinity + 1. The truly correct answer is "(the infinite set of integers greater than zero) times (the infinite set of rational numbers) plus one.

    Reply
  • September 26, 2017 at 12:23 am
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    I have a square house. each wall faces south, I see a bear outside.. what type of bear is it?

    Reply
  • September 26, 2017 at 12:23 am
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    If the question doesn't specify that it is true North, could I not just say that after I went 1 mile south I spun a certain amount of degrees that would make the destination of travelling 1 mile west, 1 mile south of the origin point?
    Sorry for my shitty explanation.

    Reply
  • September 26, 2017 at 12:23 am
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    I thought of the North Pole quite soon after the question was asked…
    I wouldn't say this question is impossible, but I guess a lot of people may find difficulty in this riddle.

    Reply
  • September 26, 2017 at 12:23 am
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    I got the answer in my first try! At first it seems impossible as we think in terms of Euclidean Geometry, but one who can think outside the box (literally!) and have an intuitiveness in geography can solve it very easily.

    Reply

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