Company's costs:
Sroc's making machine = $8000
Ads = $4000
For each manufactured pair of Sroc shoes = $9
We add them to find the cost equation in terms of x manufactured pair of Srocs:
[tex]\begin{gathered} C(x)=8000+4000+9x \\ \\ \Rightarrow C(x)=9x+12000 \end{gathered}[/tex]
There are two options for the selling price:
[tex]\begin{gathered} P_1(x)=49x \\ P_2(x)=39x \end{gathered}[/tex]
We use each of them to find out how many Srocs we need to sell in order to have a null profit:
[tex]\begin{gathered} 49x=9x+12000 \\ 40x=12000 \\ x=300 \end{gathered}[/tex][tex]\begin{gathered} 39x=9x+12000 \\ 30x=12000 \\ x=400 \end{gathered}[/tex]
As we can see, we need to sell only 100 pairs of Srocs more to recover the investment. Therefore, we choose the selling price Pâ‚‚:
[tex]\text{ Selling price: \$39}[/tex]
Finally, we have already found how much of the product must be sold to break even:
[tex]\text{ Answer: 400 pairs of Srocs}[/tex]