Question 1200577
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A plane with a tailwind flew 1920 mi in 8 hours. On the return trip, against the wind, the
plane flew the same distance in 12 hours. What is the speed of the plane in calm air and
the speed of the tailwind?
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<pre>
The effective speed with    the wind is  {{{1920/8}}} = 240 miles per hour.

The effective speed against the wind is  {{{1920/12}}} = 160 miles per hour.


In other words,

    u + v = 240
    u - v = 160,

where u is the speed of the aircraft in still air and v is the speed of the wind.


To solve equations, add them.  You will get

    2u = 240 + 160 = 400,  u = 400/2 = 200.


Then from the very first equation

    v = 240 - u = 40.


<U>ANSWER</U>.  The speed of the airplane in still air is 200 miles per hour.

         The speed of the wind is 40 miles per hour.
</pre>

Solved.