<PRE><B>Question 1066862</B>
Is the trip up the same distance as the trip back down?


{{{9*u=15*b}}} for uP and bACK times


{{{system(9=r-c,15=r+c)}}} for r rate if no current, c for rate  of just the current - this is the system needed.


ELIMINATION METHOD

Add corresponding members.
{{{(r-c)+(r+c)=9+15}}}
{{{r-c+r+c=24}}}
{{{2r=24}}}
{{{highlight(r=12)}}}------boat speed in still water.
-
Subtract corresponding members.
{{{(r+c)-(r-c)=15-9}}}
{{{2c=6}}}
{{{highlight(c=3)}}}------speed of the river current</PRE>