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

d=rt
Because the distances are the same we have:
40t=120(t-3)
40t=120t-360
40t-120t=-360
-80t=360
t=-360/-80
t=4.5 hours after the car leaves the station they will meet.
Proof:
40*4.5=120(4.5-3)
180=120*1.5
180=180