Question 1189959
<pre>
r, boat speed in still water
c, speed of the river current

                  SPEEDS      TIME        DISTANCE(kilometers)

UPSTREAM           r-c          4          152

DOWNSTRM           r+c          4          232
</pre>
{{{RATE=DISTANCE/TIME}}}


{{{system(r-c=38,r+c=58)}}}


You can finish.