C=[md]/[md+mH2O]*100 => C[md+mH2O] = md*100 => C*md+C*mH2O = md*100 => C*mH2O = md*100-C*md => C*mH2O = md(100-C) => mH2O = md(100-C)/C = 60(100-15)/15 = 340g apa
ms=md+mH2O = 60+340 = 400g sol
sau
C=md/ms*100 => ms=md*100/C = 60*100/15 = 400g sol.
ms=md+mH2O =>mH2O = ms-md = 400-60=340g