Answer:
1 hot dog costs $0.75
1 bratwurst costs $1.35
Step-by-step explanation:
Let x and y be the price per dozen of hot dogs and bratwursts respectively.
The first day they sold 8 dozen hot dogs and 13 dozen bratwursts for $282.60
8x + 13y = 282.60
The second day they sold 10 dozen hot dogs and 15 dozen bratwursts for a total of $333.00
10x + 15y = 333
and we have the linear system
8x + 13y = 282.60
10x + 15y = 333
which can be written in matrix form as
[tex]\bf \left(\begin{array}{cc}8&13\\10&15\end{array}\right)\left(\begin{array}{c}x\\ y\end{array}\right)=\left(\begin{array}{c}282.60\\333\end{array}\right)[/tex]
The solution would be given by
[tex]\bf \left(\begin{array}{c}x\\ y\end{array}\right)=\left(\begin{array}{cc}8&13\\10&15\end{array}\right)^{-1}\left(\begin{array}{c}282.60\\333\end{array}\right)[/tex]
We have
[tex]\bf \left(\begin{array}{cc}8&13\\10&15\end{array}\right)^{-1}=\left(\begin{array}{cc}-3/2&13/10\\1&-4/5\end{array}\right)[/tex]
hence
[tex]\bf \left(\begin{array}{c}x\\ y\end{array}\right)=\left(\begin{array}{cc}-3/2&13/10\\1&-4/5\end{array}\right)\left(\begin{array}{c}282.60\\333\end{array}\right)=\left(\begin{array}{c}9\\ 16.2\end{array}\right)[/tex]
Now,
if a dozen hot dogs cost $9, 1 hot dog costs 9/12 = $0.75
if a dozen bratwursts cost $16.2, 1 bratwurst costs 16.2/12 = $1.35
