I like your presentation better than mine.
I used:
Conc =
[(Vol1 * Conc1) + (Vol2 * Conc2)] / (Vol1 + Vol2)
and solved for
Vol2 quite roundabout while you came up with the more direct
Vol2 formula:
Vol2 = - (
Vol1 * (
Conc1 -
Conc)) / (
Conc2 -
Conc)
My algebra is far too dodgy to get
Vol2 all by itself... I might be a chemist, but I've always been weak with math!