Mach Number Calculation  

Object Speed :
v = M*a
Speed of Sound :
a = v/M
Where,
M = Mach Number,
v = Object Speed,
a = Speed of Sound.
Example:
Calculate the Mach Number for the given details.
Object Speed (v) = 25 m/s
Speed of Sound (a) = 20 m/s
Solution:
Apply formula:
M = v/a
M = 25/20
M = 1.25
Mach Number (M) = 1.25