Question 984733
<pre>

GOING         r             ()          d
RETRG         v             ()          d
Total                       t


r=40,v=45,t=4
unknown variables: d

</pre>



Basic uniform rates rule for travel, RT=D relating rate, time, distance.  Use the idea to fill the missing time expressions.


<pre>

GOING         r             d/r          d
RETRG         v             d/v          d
Total                       t

</pre>


Equation from the data is  {{{d/r+d/v=t}}}.


STEPS TO SOLVE FOR d:


{{{d(1/r+1/v)=t}}}
{{{d(v+r)/(rv)=t}}}
{{{highlight(d=rvt/(v+r))}}}


Substitute and evaluate.