How fast is mach 7?

Let's do the math. We know that the speed of sound, also known as mach, is 1,010 feet per second. Six times that equals 6,060 feet per second. So, if we are going 6,060 feet in 1 second, that mean in one hour we can go 21,816,000 feet in one hour. (60*60*6060). Now divide this by 5,280 feet (1 mile) and we have 4,132 MPH.