A tank full of water is leaking at a constant rate for 15 minutes. The equation is y = -8 + 500 describes the amount of water in the tank, where y is the number if liters and x is the number of minutes that has elapsed since the tank started leak. Which statment is true?

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?