Question 1147720
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<pre>

Let "d" be one way distance, in miles.


Then the total distance was 2d, while the total time was 9+4 = 13 hours.


The average rate of 40 mph is the total distance 2d divided by the total time 13 hours.


Therefore, your equation is


    40 = {{{(2d)/13}}}.


From the equation,  


    2d = 40*13,

     d = {{{(40*13)/2}}} = 20*13 = 260 miles.


<U>ANSWER</U>.  One way distance is 260 miles long.
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Solved.