Question 1119092
<pre>
                  SPEED         TIME           DISTANCE
CAR               r+30          540/(r+30)       540
TRUCK              r            540/r            540
DIFFERENCE                       3
</pre>


Truck's time is larger than the car's time.

{{{540/r-540/(r+30)=3}}}-------simplify and solve this for r.

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{{{180/r-180/(r+30)=1}}}

.
.
{{{r^2+30r-5400=0}}}


{{{r=(-30+sqrt(22500))/2}}}


{{{highlight(r=60)}}}------truck speed


{{{r+30=highlight(90)}}}------car speed