Se utilizeaza relatia: c=mdx100/ms-----> md=cxms/100
ms1= 200g
c1=90%------> md1= 90x200/100=> 180g
ms2=600g
c2=30%----> md2= 30x600/100=> 180g
ms3=900g
c3= 45%------> md3= 45x900/100= > 405g
c4/100= md4/ms4, unde md4= md1+md2+md3
ms4= ms1+ms2+ms3
a. calculeaza md4
b.calculeaza c4