ms1 = 10g, c1% = 25%
md2 = 3g
-----------------------------/--
c%final = ?%
----------------------------//--
stim ca c% = mdx100/ms
=> md1 = ms1xc1/100 = 10x25/100 = 2,5g zahar
md.final = md1+md2 = 2,5+3 = 5,5g
ms.final = ms1+md = 10+3 = 13g
=> c%final = 5,5x100/13 = 42,31%