Question 1205976
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Let x be the speed of the boat in still water.  Then x+5 is its speed downstream and x-5 is its speed upstream.<br>
The times are the same, so the ratio of distances is the same as the ratio of speeds:<br>
{{{(x+5)/(x-5)=19/9}}}
{{{19(x-5)=9(x+5)}}}
{{{19x-95=9x+45}}}
{{{10x=140}}}
{{{x=14}}}<br>
ANSWER: 14mph<br>