Question 892706
Assign some variables for RT=D, uniform rates travel, rate time distance.


r = rate of truck
r+30 = rate of car
d = distance truck travels


___________________speed________time________distance_____EQUATIONS
CAR________________r+30_________t-3_________540__________{{{highlight_green((r+30)(t-3)=540)}}}
TRUCK_______________r____________t__________540__________{{{highlight_green(rt=540)}}}


The rest of the solving process is arithmetic or algebraic steps.
Two equations in two unknowns r and t.  The system is not linear;
a couple of substitutions will be needed during the process.