Let:
x = Amount of first brand
y = Amount of second brand
so:
[tex]0.09x+0.14y=0.13(220)[/tex]where:
[tex]y=220-x[/tex]So:
[tex]\begin{gathered} 0.09x+0.14(220-x)=28.6 \\ 0.09x+30.8-0.14x=28.6 \\ -0.05x=28.6-30.8 \\ -0.05x=-2.2 \\ x=\frac{-2.2}{-0.05} \\ x=44 \end{gathered}[/tex]so:
[tex]\begin{gathered} y=220-44 \\ y=176 \end{gathered}[/tex]Answer:
44 mm of the first brand
176 mm of the second brand