Question 22105
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River flows at 2 mph. Phil can paddle in still water at 8 mph. If he is 4 miles downstream from a log floating toward him, 
how long will it take him to reach the log?
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        The solutions in the posts by @Paul and by @JWG both are incorrect.

        For the correct solution see that follows in my post.



<pre>
According to the problem's context, Phil paddles upstream, while the log is floating toward him, i.e. downstream.

The Phil effective rate relative the river's banks is 8-2 = 6 miles per hour.

The log floats toward Phil with the rate 2 miles per hour, so their approaching rate is 6+2 = 8 miles per hour.


Hence, the time when Phil will reach the log is  {{{4/8}}} = {{{1/2}}} of an hour, or 30 minutes.   <U>ANSWER</U>
</pre>

Solved.