okay so if you have 80 feet per second
there are 60 seconds in a minute
so 60 *80 which is 480 ft per min
there is 60 minutes in an hours so 480 times 60 which is 28,800 feet, then you have to know there are 5,280 feet in a mile.
Divide 28,800 by 5,280 and you get 5.45 miles per hour, rounded, the answer would be 5.5 miles per hour