Question 1201033
<pre>
         SPEED        TIME         DISTANCE

CAR        r          480/r          480

BUS        r+15       570/(r+15)     570
</pre>
The description is that the time quanties are equal.

{{{480/r=570/(r+15)}}}


Another way is to give a variable to the speed of the BUS.
If b, speed of bus, then
{{{480/(b-15)=570/b}}}------simplify and solve for b.