Answer
Revenue = $\begin{array}{l}
SF\\
LA
\end{array}\left[\begin{array}{c}{64,000}\\{22,500}\end{array}\right]$
Work Step by Step
The column matrix for the price data: $P=\left[\begin{array}{l}
30\\
10\\
15
\end{array}\right]$
The sales data (quantity) matrix: $Q=\left[\begin{array}{ccc}{700}&{1,300}&{2,000}\\{400}&{300}&{500}\end{array}\right]$
We calculate the revenue as the product of price and quantity, but
we want the matrix multiplication to be defined.
The quantity matrix is a 2$\times$3 matrix and the price matrix is 3$\times$1.
$QP$ is defined (PQ is not).
So, we multiply $QP=R$
$R=\left[\begin{array}{ccc}{700}&{1,300}&{2,000}\\{400}&{300}&{500}\end{array}\right]\left[\begin{array}{l}
30\\
10\\
15
\end{array}\right]$
$=\left[\begin{array}{c}{700(30)+1,300(10)+2,000(15)}\\{400(30)+300(10)+500(15)}\end{array}\right]$
$=\left[\begin{array}{c}{64,000}\\{22,500}\end{array}\right]$
