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anonymous

  • 5 years ago

I have a distance problem and I know the equation is d=rt. I'm just not sure how to solve the problem: A flight crew flew 420 km in 3 h with a tailwind. Flying against the wind, the flight crew flew 440 km in 4 h. Find the rate of the flight crew in calm air and the rate of the wind.

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  1. anonymous
    • 5 years ago
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    the total distance traveled divide by total amount time should give you an average of how much traveled per hour

  2. anonymous
    • 5 years ago
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    so it would be 420/3? and 440/4 to get the rate?

  3. anonymous
    • 5 years ago
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    since you are looking for a rate of travel in calm air, i think (420+440)/(3+4) should do it

  4. anonymous
    • 5 years ago
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    ok Thank you so much!!

  5. anonymous
    • 5 years ago
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    How would I find the rate of the wind?

  6. anonymous
    • 5 years ago
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    is the rate of the wind considered same for both cases?

  7. anonymous
    • 5 years ago
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    I guess it would be....the answer I get for the first part is 122.8 km/h. Do I use that answer to determine the rate of the wind?

  8. anonymous
    • 5 years ago
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    one way to find out is - since you have the rate of travel at calm wind, you can subtract rate of travel at either tail wind or against the wind from calm wind

  9. anonymous
    • 5 years ago
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    wind=15 km/hr, aircraft speed = 125 km/hr

  10. anonymous
    • 5 years ago
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    i don't think you can just add the rate of travel since the time at which air plane travels is different

  11. anonymous
    • 5 years ago
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    i think the rate of wind might be different for both cases

  12. anonymous
    • 5 years ago
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    @robtobey, how did you arrive at 125 km/h = aircraft speed and 15 km/hr = wind? Was the original equation wrong or was mymath wrong? :)

  13. anonymous
    • 5 years ago
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    msayer3, There is no indication from the problem statement that the wind velocity changed from my point of view.

  14. anonymous
    • 5 years ago
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    yeah, that's what i'm wondering.

  15. anonymous
    • 5 years ago
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    I will post the solution in a few minutes.

  16. anonymous
    • 5 years ago
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    ok...thank yo very much

  17. anonymous
    • 5 years ago
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    r*t = d r = d/t Let x = the wind speed First flight leg: \[r+x==\frac{d}{t}\text{/.} \{d\to 420,t\to 3\} \]r + x = 140 Second flight leg:\[r-x=\frac{d}{t}\text{/.} \{d\to 440,t\to 4\} \]r - x = 110 2 r = 140 + 110 r = 125 r + x =140 125 + x = 140 x = 15

  18. anonymous
    • 5 years ago
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    I use Mathematica for the calculations /. means sort or, "replace the symbols as follows"

  19. anonymous
    • 5 years ago
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    Ok...I think I got it now. Thank you again for your help.

  20. anonymous
    • 5 years ago
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    Glad I could help you out.

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