Răspuns:
Explicație:
md adaugat =20g sare
ms1= 300g sol.
c1= 15%
c2 =?
c1= md1 .100 : ms1
md1= c1 . ms1 : 100
md1= 15 . 300 : 100 = 45g sare
md 2 = md1 + md adaug.
md 2= 45 + 20= 65g sare
ms2 = ms1 + md adaug.
ms 2 = 300 + 20= 320g sol.
c2= md2 . 100 : ms2
c2= 65 . 100 : 320 = 20,31 %