ms1= 200g, c1% = 20%
ms2= 600g, c2% = 80%
stim ca c% = mdx100/ms
=> md1 = ms1xc1/100 = 200x20/100 = 40 g
=> md2 = ms2xc2/100 = 600x80/100 = 480 g
c%.final = md.finalx100/ms.final
=> md.final = md1+md2 = 40+480 = 520g
ms.final = ms1+ms2 = 200+600 = 800g
=> c%.finala = 520x100/800 = 65%