Respuesta :

73 feet per second

Steps-
Miles to cover- 50 miles = 50*5280 feet = 264,000 feet
Time it takes- 1 hour = 1*60*60 seconds = 3,600 seconds

So speed is- 264,000 feet per 3,600 seconds = 264,000 / 3,600 = 73.33 ft per second