Question 1025058
Travel rates rule to relate the numbers, RT=D, and then T=D/R;

<pre>
             rate            time         distance

JOG          r+2&1/2         {{{10/(r+2&1/2)}}}      10

WALK         r               {{{10/r}}}            10

TOTAL                         6             20
</pre>

Do you see what to do from this?