Question 1170345
<pre>
                SPEED       TIME          DIST.

smith            r+8       168/(r+8)      168

jones            r         168/r          168

difference                 1/2
</pre>
{{{168/r-168/(r+8)=1/2}}}-------simplify and solve.

.

.
{{{r^2+8r-2688=0}}}

{{{r=(-8+sqrt(64+4*2688))/2}}}

{{{highlight(r=48)}}}
and
{{{highlight(r+8=56)}}}