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Homework Help: Speed Problem

  1. Sep 21, 2009 #1
    1. The problem statement, all variables and given/known data

    You and a friend each drive 50 km. You travel at a uniform speed of 91.4 km/hr and your friend travels at a constant speed of 88.3 km/hr. How long will you wait for your friend?

    2. Relevant equations

    3. The attempt at a solution

    So I thought I could just set up a ratio and cross-multiply to get the hrs. traveled by each person. I got .547hrs. for "me" and .566hrs. for "my friend". Then subtract, the difference being the answer. However, I am doing this on a computer-generated exercise and it is telling me that .019hrs. is incorrect. Why isn't this right?
  2. jcsd
  3. Sep 22, 2009 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    It looks like you did this correctly, I get the same answer. It could be they expect a different number of significant figures in the answer, or they expect different time units for some reason.
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