aplici realtiile: c%=mdx100/ms, unde ms= md+m,apa; faci doar inlocuirile necesare!!!!
1. md=60g, ms=300g c=60x100/300=.....................
2.20/100= md/4000---> md=...................
20/100=md/2000---> md=..................
20/100= md/1000---> md=..................... calculeaza !!!!!
md- masa de substanta dizolvata
ms= masa de solutie( masa solvatului + masa solvantului)