Question 1060598
<pre>
             SPEED         TIME       DISTANCE
DOWN         r+2                        8
UPRIVER      r-2                        4
Total                       2


             SPEED         TIME       DISTANCE
DOWN         r+2           8/(r+2)      8
UPRIVER      r-2           4/(r-2)      4
Total                       2
</pre>

{{{highlight(8/(r+2)+4/(r-2)=2)}}}