In this problem we are asked to find the total advertising cost of the CDs for three countries. This can be represented by a multiplication of matrices.
A is an 1x3 matrix and represents The cost of advertising for both bands
B must be a 3x1 matrix and represents The total number of CDs sold in each country
So, according to the multiplication of matrix rules, the result of multiplying a 1x3 matrix by a 3x1 matrix is an 1x1 matrix.
Let's begin:
[tex]A=\left[\begin{array}{ccc}2&1.5&1\end{array}\right][/tex]
[tex]B=\left[\begin{array}{ccc}40000\\50000\\30000\end{array}\right][/tex]
The correct way to multiply these matrices is as follows:
[tex]AB=\left[\begin{array}{ccc}2&1.5&1\end{array}\right]\left[\begin{array}{c}40000\\50000&30000&\end{array}\right][/tex]
Then:
AB=[2(40000)+1.5(50000)+1(30000)]
AB=[80000+75000+30000]
Finally:
AB=[185000]
The answer is $185000, which is the total advertising cost for all three countries
