Question 735210
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How far from an airport can an airplane fly and return in 8 hours, if its outgoing speed is 160 kilometers per hour 
and its returning speed is 240 kilometers per hour?
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<pre>
Let's 'd' be this unknown distance to fly from the airport, in kilometers.


Then the time to fly out is      {{{d/160}}}  hours;

     the time to return back is  {{{d/240}}}  hours,

and the sum of these two pieces of time is 8 hours


    {{{d/160}}} + {{{d/240}}} = 8.


It is your equation to find 'd'.


To find it, multiply all the terms by the least common denominator, which is 480.
You will get

    3d + 2d = 8*480,

      5d    = 3840,

       d    = 3840/5 = 768 kilometers.


<U>ANSWER</U>.  The distance to fly from the airport is 768 kilometers.
</pre>

Solved.