hehehe highkoo
well, i guess calculating this equation from a known formula is eight grade maths, but actually figuring the formula out by yourself, is something more difficult and that's what sec was asking about
back when i was still in school (i'm 26 now) i have always been pretty good in math.. (finished 2 hour math tests after an hour with a perfect score, even though i have skipped school for more than 3 weeks prior to the test and nobody, neither me nor the teacher, could explain how i managed to do this), so i guess i simply have a pretty good understanding when it comes to logical thinking and hence math..
even though i didn't do any difficult calculations or equations the last, let's say, 8 years, it wasn't difficult and took me not more than about 15 minutes
i simply sat down, started thinking about it for a minute or two, and started calculating and fortunately my first thoughts of how to calculate this were right..
then i tried the equation using some logic bpm's (as mentioned in the context where you'd get an answer of 0% or so) and that prooved me right
the last step was actually trying this within adobe audition and after this was working properly as well i figured i was right