Dau coroană. Va rog rapid!!

ms1= 400g, c1% = 25%
m.apa.adugata = 100g
c% = mdx100/ms
=> md = ms1xc1/100 = 400x25/100 = 100 g
ms2 = ms1+m.apa.adaugata = 400+100 = 500g
=> c2% = mdx100/ms2 = 100x100/500 = 20%