c,final = mdx100/ms, unde
md= md(solutie)+100, g
ms= md(solutie)+m,solutie+m,apa= md(solutie)+200+100+400, g
md(solutie)= cxms/100=40x200/100=80g
md= 80+100=180g
ms= 80+200+100+400=780g
c= 180x100/780=....................calculeaza !!!!
Atentie, am transformat 400ml apa in 4oo g apa, pentru ca apa are densitatea 1g/ml