Question 524868
Car A Speed = a mph
Car B Speed = a+20 mph

Car A will travel total distance = a * 3 = 3a mph
Car B will travel total distance = (a+20) * 3 = 3a+60 mph

They are traveling in oppisite directions so 
sum of the distance travelled by both Cars = 330 miles

3a+3a+60=330
6a=330-60
6a=270
6a/6=270/6
a=45

Car A Speed = a=45 mph
Car B Speed = a+20=45+20=65 mph

Check

Distance travelled by Car A = 45 * 3 = 135 miles
Distance travelled by Car B = 65*3 = 195 miles
Total Distance b/w Car A and B = 135+139 = 330 miles