la punctul f)
se utilizeaza relatia
c= mdx100/ms
c3=md3x100/ms3, unde md3=md1+md2+md
ms3= ms1+ms2+md= 80+160+md=240+md
md1= c1xms1/100= 4x80/100g=3,2g
md2= c2xms2/100= 40x160/100g=64g
33,538= (64+3,2+md)x100 / (249+md)
33,538(240+md)= 100(67,2+md)========> md=20g zahar
