Question 1140034
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Let x be the Alma's rowing speed in still water.


Then the speed downstream is (x+4) mph, and the speed upstream is  (x-4) mph.


The time downstream  is  {{{130/(x+4)}}} hours; the time upstream is  {{{130/(x-4)}}} hours.


The "time" equation is


{{{130/(x-4)}}} - {{{130/(x+4)}}} = 16   hours.


Solve it for x and get the answer.
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