How do I invert my function to return the input as output $v_{Out} = \frac {vIn - v_{Min}} { v_{Max}}$

Question

I have an normalization function to convert values into a $0$ to $1$ range using the following function, but I'm stuck on how to turn the output into it's original format.

$$v_{Out} = \frac {vIn - v_{Min}} { v_{Max}}$$

Example:
$$0.25 = \frac {50 - 25} {100}$$

How do I turn this output of $0.25$ back into the input of 50 using the inverse of my function?