Please help me on this and I’ll give you 10 points for this because I really don’t understand it’s a water hopefully thank you so much but please help me because I really don’t understand this thank you

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?