Question 838897
The time taken by both the cars is same = 3 hours

let speed of one be x kmph
other's speed is (x+18) kmph

3x+3(x+18) = 600

3x+3x+54=600

6x+54=600

6x= 546

x= 546/6
x= 91 km/h

x+18 = 91+18 = 109 km/h ------------- second car