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Homework Help: Train question

  1. Jun 26, 2008 #1
    1. The problem statement, all variables and given/known data
    What is the best way to do this problem? It looked easy but when I the solution just wasn't clicking for me. I tried to calculated the average speed of the last 20 miles explicitly and it took me a really long time and I had to crudely approximate the answer...I am pretty sure there is a simple way to do this.


    2. Relevant equations



    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. Jun 26, 2008 #2

    Doc Al

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    Staff: Mentor

    Hint: Figure out the time it takes for the total trip and each segment.
     
  4. Jun 26, 2008 #3
    That's pretty much what I did. The first 30 miles take 3/4 hr and the last 20 miles take 13/36 hr. So then I just need to figure out whether 20*36/13 is greater than 45 by long division, right?
     
  5. Jun 27, 2008 #4
    That's correct.
     
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