[tex]15) \\ \\ md_{1} = \frac{40 \times 10}{100} = 4 \: g \\ \\ md _{2} = \frac{30 \times 40}{100} = 12 \: g \\ \\ md_{3} = md_{1} + md_{2} = 4 + 12 = 16 \: g \\ \\ ms_{3} = ms_{1} +ms_{2} = 40 + 40 = 80 \: g \\ \\ c_{3} = \frac{md_{3} }{ ms_{3}} \times 100 = \frac{16}{80} \times 100 = 20\% \\ \\ 19) \\ \\ c = \frac{md}{ms} \times 100 \\ \\ ms = md + m_{apa} \\ \\ ms = md + 475 \\ \\ 5 = \frac{md \times 100}{(md + 475)} \\ \\ 100md = 5md + 2375 \\ \\ 95md = 2375 \\ \\ md = 25 \: g \: zahar \\ \\ 20) \\ \\ c = \frac{md}{ms} \times 100 = > md = \frac{c \times ms}{100} = \frac{10 \times 200}{100} = 20 \: g \: NaCI \\ \\ ms = md + mH2O = > mH2O = ms - md = 200 - 20 = 180 \: g \\ \\ md = \frac{(c \times mH2O)}{(100 - c)} = \frac{20 \times 180}{100} - 20 = 45 \: g \: NaCI \\ \\ m \: NaCI \: adugat = 45 - 20 = 25 \: g \: NaCI [/tex]
