Question 1131716
<pre>
         SPEED          TIME       DISTANCE

Mark        r           4+1=5        d
      
Imani       r+9           4          d
</pre>

{{{system(5r=d,4(r+9)=d)}}}

-

{{{5r=4(r+9)}}}

{{{5r=4r+36}}}

{{{5r-4r=4r+36-4r}}}

{{{highlight(r=36)}}}-------------Marks speed