c=mdx100/ms unde ms= rox Vs
40/100= md1/ 400x 1,437-------------------------> md1= calculeaza
20/100= md2 /800x 1,225---------------------------> md2= calculeaza
c3= (md!+md2)/(400x1,437+800x1,225)-----------> calculeaza , trebuie sa-ti dea o valoare cuprinsa intre 40 si 20 !
