A car travels a total distance of 300 miles. For the first part of the trip, the car maintains an average speed of 60 miles per hour. For the second part of the trip, the car maintains an average speed of 45 miles per hour. If $x$ represents the number of minutes spent traveling at 60 miles per hour and $y$ represents the number of minutes spent traveling at 45 miles per hour, which equation represents the total distance traveled?