Question 998221
<pre>
              speed        time       distance
Stefan        21           t+3          d
Shreya        35            3           d
</pre>

Question asks for t.  Note that both went the same distance upon their meeting.


{{{system(21(t+3)=d,35*3=d)}}}


{{{21(t+3)=35*3}}}


{{{t+3=35*3/21}}}


{{{highlight(t=35*3/21-3)}}}


{{{highlight(highlight(t=2))}}}