Question 1095688
<pre>
               SPEED         TIME           DISTANCE

firstpart      r+10         {{{120/(r+10)}}}     120

secondpart     r            {{{100/r}}}       100

Total                        4
</pre>

Solve the equation  {{{120/(r+10)+100/r=4}}}.


-

{{{30/(r+10)+25/r=4}}}

.

.