Two cars start from the same point and ride in opposite dire

Two cars start from the same point and ride in opposite directions. One car travels 30 mph slower than the other car. in six hours they are 600 miles apart. what is the rate of each car? D=rt

Solution

Let rate of one car be x, rate of other is (x-30)
given t=6
given d=600 at t=6
d1 = x*6
d2 =(x-30)*6
D1+D2=600=x*6+(x-30)*6=6(2x-30)
divive both sides by 6
100=(2x-30)
add 30 both sides
130=2x
divide both sides by 2
65=x
(x-30)=35
checking
65-35=30 ok
(65 +35) 6=100*6=600 ok