ajutor la acesta problema!!

c=mdx100/ms
c1=15%
ms1=700g
md1= c1xms1/100= 105g sare
c2=md1x100/ms2 ,,,,,,unde md2= md1+m,sare=105+100=> 205g
ms2=ms1+m,sare+ m,apa= 700+100+200=> 1000g
c2= 205x100/1000=...........................calculeaza !!!!