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Homework Help: The distance a fly flies

  1. Jan 18, 2006 #1
    Two cyclists start cycling towards each other with an even speed of 10km/h. They start of 20km away from each other. At the same time a fly starts from one of them and flies to the other one, back to the first, and so on until they meet. How far has the fly flown in the end if it flew with a speed of 15km/h?

    I'm thinking it has to be 15km, since the two guys will meet half way after 1 hour, and the fly flies 15km in one hour. Can someone confirm this?
  2. jcsd
  3. Jan 18, 2006 #2
    i confirm, you got it right :biggrin:
  4. Jan 19, 2006 #3


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    Just for fun, did anyone try the von Neumann method to solve the problem - with different speeds for the cyclists? :)
  5. Jan 19, 2006 #4
    Not yet, but as you said, it should be done - just for fun.
  6. Jan 19, 2006 #5
    That is exactly how my calc 2 teacher introduced us to series, starting with that question then telling the story about Von Neumann.
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