Question 1168039
.
<pre>

Write the "time" equation


    {{{d/20}}} - {{{d/80}}} = 3  hours,


where "d" is one way unknown distance.


It is your basic equation.


To solve it, multiply both sides by 80.  You will get


    4d - d = 240

    4d     = 240

     d     = 240/3 = 80 miles.    <U>ANSWER</U>
</pre>

Solved.