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-   -   Jet speed against the wind (https://www.askmehelpdesk.com/showthread.php?t=418285)

  • Nov 22, 2009, 09:04 AM
    rpmacs
    Jet speed against the wind
    A jet takes the same time to travel 2500 km %.555 with the wind as it does to travel 1900 km 2.555against the wind. If its speed relative to the air is 450 km/hr, what is the speed of the wind?

    I came up with a wind speed of 3 Km/hr
    Not sure how to put in a formula.
  • Nov 22, 2009, 09:20 AM
    galactus
    What is the %.555 and the 2.555?

    The problem says, "in the same amount of time". That is a clue to equate the times.

    When the plane is flying with the wind, it is being helped along. So, we add the rate of the wind to the rate of the plane.

    Likewise, when it is flying against the wind it is being held back. So, we subtract the rates.

    This is just d=rt. Then, t=d/r



    Solve for w, the speed of the wind. The wind blows stronger up there where the plane is than down here on the ground.

    It is faster than 3 kph. Unless I am missing something. I am confused by the %.555 and 2.555.
  • Nov 22, 2009, 11:07 AM
    rpmacs

    I came up with:-

    2500w+2500*450=1900w+1900*450

    -4400w=-270000

    w=61.36

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