Question 1193557
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Here is a different method for solving this type of problem that I personally find easier than the traditional algebraic solution shown by the other tutor.<br>
If x is the speed of the current, then the downstream speed is 15+x and the upstream speed is 15-x.<br>
The upstream and downstream times are the same, and the downstream distance is 2 times the upstream distance.  That means the downstream speed is 2 times the upstream speed:<br>
{{{15+x=2(15-x)}}}
{{{15+x=30-2x}}}
{{{3x=15}}}
{{{x=5}}}<br>
ANSWER: The speed of the current is 5mph.<br>