Question 1173839
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<pre>

Let x be the slower rate, in miles per hour.

Then the faster rate is (x+4) mph.


The time equation is


    {{{13/x}}} + {{{17/(x+4)}}} = 2   hours.    (*)


The solution/(the answer) is absolutely clear (obvious):  x = 13 mph.    <U>ANSWER</U>



<U>CHECK</U>.  {{{13/13}}} + {{{17/(13+4)}}} = 1 = 1 = 2 hours.   ! Correct !
</pre>

Solved (mentally).


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Alternatively, you can solve equation (*) by reducing it to a quadratic equation, if you want.