Notam cu X cantitatea de zahar
Avem formula pentru concentratia procentuala:
md/ms * 100 = c
unde
c = concentratie
md = masa dizolvata
ms = masa solutie
in cazul problemei noastre:
c = concentratie = 5%
md = masa dizolvata = X
ms = masa solutie = 475g + X
Inlocuim in ecuatie si obtinem:
X / (475 + X) * 100 = 5 =>
=> 100X / (475 + X) = 5 =>
=> 100X = 2375 + 5X =>
=> 95X = 2375 =>
=> X = 2375 / 93 =>
=> X = 25
