i need the formula
The three ratios of minutes:quantity are, respectively, about 0.3177, 0.5183 and 0.6634.
What is the "it" to which you refer (indefinite antecedent).
If you thought it would be useful, you could take this data as 3 points on a function, and try to curve fit it using a graphing calculator. That would be a way to find (empirically) various formulas, and presumably you would choose the best fit to this small list of data points.