Question 1148068
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<pre>

Let x be the speed of the wind, in miles per hour.


Then the speed of the airplane with the wind is  (220+x) miles per hour;

                               against the wind  (220-x) miles per hour.


The time equation is


    {{{540/(220+x)}}} = {{{340/(220+x)}}}.


To solve it, cross-multiply


    540*(220-x) = 340*(220+x).


Simplify and solve


    540*220 - 540x = 340*220 + 340x


    540*220 - 340*220 = 340x + 540x

    
    x = {{{(540*220 - 340*220)/(340+540)}}} = 50.


<U>ANSWER</U>.  The wind speed is 50 miles per hour.
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Solved.