Question 1159172
r, speed of boat in still water


{{{20/(r-5)-20/(r+5)=8&1/3}}}--------solve for r.


Divide both sides by 5, multiply both sides by 3,

{{{12/(r-5)-12/(r+5)=5}}}

.

.

{{{120=5r^2-125}}}
-
{{{24=r^2-25}}}
{{{24+25=r^2}}}
{{{49=r^2}}}
{{{highlight(r=7)}}}





....

{{{highlight(r=)}}}