Two cars start out 500 miles apart. Car A is to the west of Car B and starts driving to the east (i. towards Car B) at 35 mph and at the same time...

Two cars start out 500 miles apart. Car A is to the west of Car B and starts driving to the east (i.e. towards Car B) at 35 mph and at the same time Car B starts driving south at 50 mph. After 3 hours of driving at what rate is the distance between the two cars changing? Is it increasing or decreasing?