I have a set of four numbers. 7.5, 18.5, 424 and 0.
Certain percentage is associated with each of it, viz 1.66%, 4.11%, 94.22% and 0.1% resp, which in total is 100%.
I want to know how these percentages were calculated? Can a generic formula be applied ?
Simply put: The individual percentage is equal to the individual number divided by the total (and multiplied by $100~\%$). The total is simply $$ \text{total} = 7.5 + 18.5 + 424 + 0 = 450 $$ Therefore, the percentages are $$ \frac{7.5}{\text{total}}, \qquad \frac{18.5}{\text{total}}, \qquad \text{etc.} $$ NB: In this case, some rounding has been applied to the numbers, so don't worry about the minor rounding details (unless you really have to!).