<PRE><B>Question 190401</B>
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Use &lt;i&gt;distance&lt;/i&gt; equals &lt;i&gt;rate&lt;/i&gt; times &lt;i&gt;time&lt;/i&gt;


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ d = rt]


Let &lt;b&gt;&lt;i&gt;t&lt;/i&gt;&lt;/b&gt; be the time in hours they spent paddling downstream.  Then the time spent paddling upstream must have been &lt;b&gt;1 - &lt;i&gt;t&lt;/i&gt;&lt;/b&gt; because the whole trip took 1 hour.


The downstream trip is then described by:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ d = 12t]


And the upstream trip is described by:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ d = 4(1-t)]


But the distance was the same both ways (unless some clown moved their campsite while they were gone, in which case you wouldn&#39;t be able to solve the problem) so:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 12t = 4(1-t)]


Solve for &lt;i&gt;t&lt;/i&gt; and you have the amount of time the downstream trip took, in hours.  Convert that to minutes and add it to 10 AM to get the answer to the question.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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