Since there are 60 seconds in a minute and 60 minutes in an hour, then there are 3600 seconds per hour. And since there are 1609 meters per mile and you have 50.1 miles, then there are 80610.9 meters per 50.1 miles. So there would be 80610.9 meters per 3600 seconds. And finally your answer is about 22.3919 m/s.
HOPE THIS HELPS!!
-FITZ-