64 km x 0.62137 = 39.76768 miles per hour
64.4 x 0.62137 = 40.016228 miles per hour
40.016228 - 39.76768 = 0.248548 miles per hour faster
1 mile =5280 feet
5280 * 0.248548 = 1312.33 feet per hour
3600 seconds per hour
1312.33 / 3600 = 0.37 feet per second faster
