How to write a dependency formula?

Question

JavaScript

There is a form in which the user himself chooses the parameters


"Percentage" can take the maximum and minimum values, that is, it is in a certain range. (not +-infinite)

You need to calculate this percentage value depending on the amount and term values. If the term increases, the percentage decreases; if the amount increases, the percentage also increases and vice versa.

In this case, it is necessary to take into account when one of the parameters is unchanged. I've been scratching my head for several days, nothing good comes out.

Answer 1

If the term increases, the percentage decreases

p ~ 1/t
Percentage is inversely proportional to time

if the amount increases, the percentage also increases

p ~ m
The percentage is proportional to money
If we combine both thoughts, we get
p=k*m/t;
m - money
t - time
k - a certain coefficient of proportionality, selected experimentally or from considerations of boundary conditions