notez datele pa care mi le-ai dat
md1= 120g
ms1=420g
prin adaugare de apa , solutia se dilueaza si rezulta c2=20%
c2= md2x100/ms2, unde md2=md1=120g
ms2=ms1+m,apa=420+m,apa
20= 120x100/(420+m,apa)
12000=20(420+m,apa)
12000= 8400+ 20m,apa-----> m,apa= 180g
