Question 1110608
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<U>One line solution</U>


<pre>
How long will it take Mark to catch up Sally = {{{(2*50)/(65-50)}}} = {{{100/15}}} = {{{20/3}}} = {{{6}}}{{{2/3}}} hours = 6 hours and 40 minutes.



<U>Explanation</U>.  The numerator 2*50 = 100 miles is the Sally's head start distance.


              The denominator (65-50) = 15 mph is their relative speed, i.e. the rate of decreasing the initial 100 km distance between them.
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