Question 1157562
.
<pre>

The condition gives you THIS "time" equation

    {{{140/x}}} = {{{147/(x+3)}}}.


where "x" is the unknown speed value under the problem's question.


Cross multiply and solve

    140*(x+3) = 147x

    140x + 140*3 = 147x

    140*3 = 147x - 140x

    140*3 = 7x

    x = {{{(140*3)/7}}} = 20*3 = 60 mph.    <U>ANSWER</U>
</pre>

Solved.