Math - How to use a percentage that stays within a range?

Having a brain fart here. So, if I have a min and max value, and I want to use a 0 - 1 float range for 0%-100%. How can I make it so that when I input 50%, I will get right in the middle of the min and max?

Something like that?:

//C#
float Map(float min, float max, float t)
{
    return min + t*(max-min);
}

Which is basically what Mathf.Lerp does ^^. “t” should be in range [0-1] and the returned value is in range [min - max].

Example:

float r = Map(3f, 15f, 0.5f);  // --> 9

float r = Mathf.Lerp(3f, 15f, 0.5f);  // --> 9