8 dlls for silver
16 dlls for brass
5 dlls profit silver
7 dlls profit spheres
Then the price is
8+5= 13 dlls for silver
16+7=23 dlls for brass
Let S and B be the amount of magnetic silver and brass sphers that are sold, respectively.
Then, Ms. Ball estimation is that
[tex]S+B\leq2000[/tex]Also, she doesn't want to invest more than 20000, so
[tex]\begin{gathered} 8S+16B\leq20000 \\ S+2B\leq2500 \end{gathered}[/tex]The objective function is
[tex]V=5S+7B[/tex]Subjected to:
[tex]\begin{gathered} S+B\leq2000 \\ S+2B\leq2500 \\ S\ge0,\text{ B}\ge0 \end{gathered}[/tex]GRAPH
The interection is at
[tex]\begin{gathered} S=2000-B \\ S=2500-2B \\ 2000-B=2500-2B \\ B=500 \\ S=2000-500 \\ S=1500 \end{gathered}[/tex]So, the extremes must be at (0,1250), (1500,500), (2000,0) , (0,0).
So, if we replace the points
[tex]\begin{gathered} V(0,1250)=5(0)+7(1250)=8750 \\ V(1500,500)\text{ = 5(1500)+7(500)=}11000 \\ V(2000,0)=5(2000)+7(0)=10000 \end{gathered}[/tex]So, the amount she will need to stock to maximize her profit is 1500 of silver and 500 of brass, and the maximum profit is going to be 11000 dlls.