Question 192971
Let,
r = rate of the slower driver.
r+30 = rate of faster driver.

In 6 hours,
Slower driver drives 6*r miles (dist = rate*time)
Faster driver drives 6*(r+30)

Totally between them they driver 600 miles.
Thus,
6*r + 6*(r+30)=600
Solving for r, we get
r (slover drivers rate) = 35 mph
r+30 (faster driver rate)= 65mph