Question 1089240
<pre>
               SPEED         TIME        DISTANCE
UP             5-c           4/(5-c)    4
BACK           5+c           4/(5+c)    4
Total                         8
</pre>

{{{4/(5-c)+4/(5+c)=8}}}


{{{highlight_green(1/(5-c)+1/(5+c)=2)}}}