To convert 60 feet into miles, we divide it by 5280(1 mile=5280 feet) and to convert 0.48 seconds into minutes, we divide it by 60(60 seconds=1 minute) and then to divide that into hours, we again divide it by 60(60 minutes=1 hour) or divide that by 60x60
Distance in miles=60/5280=0.0211 miles
Time in hours= 0.48/(60x60)=1.3x10^-4 hours.
Speed in mph=0.011/1.3x10^-4=85.2 mph