Here's a breakdown:

* Speed of sound: Varies depending on the medium (air, water, etc.) and temperature. In standard air at sea level, it's approximately 767 mph (1235 km/h).

* Supersonic: Anything faster than that.

* Mach number: A way to express supersonic speeds. Mach 1 = the speed of sound. Mach 2 = twice the speed of sound, and so on.

So, there's no single "supersonic speed." It's a range of speeds, all faster than the speed of sound.

For example:

* A commercial jetliner: Flies at subsonic speeds (slower than the speed of sound).

* A fighter jet: Can reach supersonic speeds (Mach 1.5 or higher).

* A supersonic missile: Travels at extremely high supersonic speeds (Mach 5 or more).