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Math Help - rate problem

  1. #1
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    rate problem

    An airplane travels 700 miles against the wind in 4 hours, and makes the return trip with the same wind in 2 hours. Find the rate of the wind.

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    Quote Originally Posted by kelsikels View Post
    An airplane travels 700 miles against the wind in 4 hours, and makes the return trip with the same wind in 2 hours. Find the rate of the wind.

    Help!
    Thanks
    Hi kelsikels,

    Let v be the speed of the airplane, let w be the speed of the wind (absolute value).

    General equation x = vt

    In our case,

    700 = (v - w) * 4 = 4v - 4w (Eqn 1)

    700 = (v + w) * 2 = 2v + 2w (Eqn 2)

    Multiply (Eqn 2) by -2

    -1400 = -4v - 4w (Eqn 3)

    Add (Eqn 1) and (Eqn 3)

    -700 = -8w

    w = 700/8 = 87.5 miles/hour
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