V.apa = 184 mL, ro = 1 g/mL
stim ca ro = m/V =>
m = roxV = 184x1 = 184 g apa
100% ...................... masa impura = 20g
80% ........................ masa pura = m g
=> m = 20x80/100 = 16 g sare pura
stim ca c% = mdx100/ms
md = m = 16 g
ms = md + m.apa = 16+184 = 200 g
=> c% = 16x100/200 = 8%