Two cars left at the same time two cars left at the same time towards each other from two points, the distance between

Two cars left at the same time two cars left at the same time towards each other from two points, the distance between which is 840 km, the speed of the first is 50 km / h, the speed of the second is 60 km / h, having driven 300 km, the first car met the second, how many hours the second car left before the first.

Find the distance traveled by the second car:
840 – 300 = 540 km.
Then his travel time was:
540: 60 = 9 hours.
The travel time of the first car is:
300:50 = 6 hours.
The time difference was:
9 – 6 = 3 hours.
Answer: the second car left 3 hours earlier than the first.