Zadanie 14.
Cena puszki farby A - x
Cena puszki farby B - y
[tex]x=0.8y\\1.4x=y+60\\1.4*0.8y=y+60\\1.12y=y+60\\0.12y=60 /:0.12\\y=500\\x=0.8*500=400[/tex]
Do pomalowania mieszkania potrzeba 1,4x farby A lub y farby B
[tex]1.4x=1.4*400=560\\y=500[/tex]
Odp. W ilosci potrzebnej do pomalowania mieszkania, farba A kosztuje 560zl, a farba B, 500zl.
Zadanie 15.
[tex]Cp=\frac{m_s}{m_r}*100\%\\\\Cp_1=3\%\\m_r_1=5kg\\\\3\%=\frac{m_s_1}{5kg}*100\%\\\frac{3}{100}=\frac{m_s_1}{5kg}\\m_s_1=\frac{3*5kg}{100}=\frac{15}{100}kg=0.15kg[/tex]
[tex]Cp_2=5\%\\m_r=5kg+m_s\\m_s=0.15kg+m_s\\\\5\%=\frac{0.15kg+m_s}{5kg+m_s}*100\%\\\frac5{100}=\frac{0.15kg+m_s}{5kg+m_s}\\\\100(0.15kg+m_s)=5(5kg+m_s)\\15kg+100m_s=25kg+5m_s\\100m_s-5m_s=25kg-15kg\\95m_s=10kg /:95\\m_s=\frac{10}{95}kg=\frac{2}{19}kg=0.105...kg\\\\\text{Nalezy dosypac okolo 105g soli}[/tex]
Zadanie 16.
[tex]Cp_1=9\%\\m_r=10kg\\9\%=\frac{m_s}{10kg}*100\%\\\frac9{100}=\frac{m_s}{10kg}\\m_s=\frac{9*10kg}{100}=\frac{90kg}{100}=0.9kg[/tex]
[tex]Cp_2=6\%\\m_r_2=m_r_1+m_{rozp}\\m_r_2=10kg+m_{rozp}\\\\6\%=\frac{0.9kg}{10kg+m_{rozp}}*100\%\\\frac6{100}=\frac{0.9kg}{10kg+m_{rozp}}\\\\6(10kg+m_{rozp})=100*0.9kg\\60kg+6m_{rozp}=90kg /-60kg\\6m_{rozp}=30kg /:6\\m_{rozp}=5kg\\\\\text{Nalezy dolac 5kg wody}[/tex]
