Question 1195933
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You and your roommate decided to take a road trip to the beach one weekend. 
You drove all the way to the beach at an average speed of 60 miles per hour. 
Your roommate drove all the way back (on the same route, but with no traffic) 
at an average rate of 75 miles per hour. If the round trip
drive took a total of 9 hours, how many miles was the trip to the beach?
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<pre>
Let d be the one way distance, in miles.


Then the trip to the beach takes  {{{d/60}}}  hours,
while the trip back takes  {{{d/75}}}  hours.


The total time equation is

    {{{d/60}}} + {{{d/75}}} = 9  hours.


To solve it, multiply both sides by 300.  You will get then

    5d + 4d = 9*300

      9d    = 9*300

       d    = 300 miles.


<U>ANSWER</U>.  The trip to the beach is 300 miles long.


<U>CHECK</U>. {{{300/60}}} + {{{300/75}}} = 5 + 4 = 9 hours, total travel time.     ! Correct !
</pre>

Solved.