Question 1145672
.
<pre>

If x is the speed of the wind, 

then  the speed of the plane with   the wind is  (235+x) mph,

while the speed              against the wind is (235-x) mph.



The "time" equation is


    {{{400/(235+x)}}} = {{{352/(235-x)}}}.


Cross multiply


    400*(235-x) = 352*(235+x).


    400*235 - 400x = 352*235 + 352x

    400*235 - 352*235 = 352x + 400x

    x = {{{(400*235 - 352*235)/(352+400)}}} = 15 miles per hour.


<U>ANSWER</U>.  The speed of the wind is 15 miles per hour.
</pre>

Solved.