Răspuns:
se foloseste relatia c=mdx100/ms, unde ms= md+m,apa
ms1=800g
c1= 10%
md1= c1xms1/100= 10x800/100g= 80g
ms2= 500g
c2= 5%
md2= 500x5/100g= 25g
solutia finala
md= md1+md2+md=80g+25g+50g=155g
ms= ms1+ms2+ md+m,apa= 800+500+50+100=>1450g
c= 155x100/1450=10,7%
Explicație: