a car leaves a train station traveling west at a speed of 40

a car leaves a train station traveling west at a speed of 40 kilometers per hour. a train leaves the station three hours later traveling west at a rate of 120 kilometers per hour. in how many hours will the train catch up to the car?

Solution

Let the time taken by tne train to meet the car be t hours
The speed of the train = 120 kmph
The distance travelled by the train in t hours = 120t
The time taken by tne car to meet the train is (t+3) hours
The speed of the train = 40 kmph
The distance travelled by the car in (t+3) hours = 40(t+3)
When they meet both distances are equal
120t = 40(t+3)
120t = 40t+120
120t-40t = 120
80t = 120
t = 120/80
t = 1h 30 m