Question 957182
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Tutor @ikleyn sets the problem up with an equation which says the two times (distance divided by rate) are equal:<br>
{{{256/(25+c)=144/(25-c)}}}<br>
That of course is one valid way to set the problem up.<br>
Another valid way to set the problem up is to use a proportion which says that, since the times are equal, the ratio of the distances is equal to the ratio of the speeds:<br>
{{{256/144=(25+c)/(25-c)}}}<br>
Clearly the two ways of setting up the problem lead immediately to identical calculations to get the answer -- so it is a matter of personal preference for which method to use.<br>