Answer :
[tex]\begin{gathered} A=\begin{bmatrix}8 & 4 \\ 10 & 6 \\ 6 & 4\end{bmatrix}_{3\times2} \\ B=\begin{bmatrix}103 & 249 \\ \end{bmatrix}_{1\times2} \end{gathered}[/tex]
1) Notice that there are three students: Sean, Kevin, and Bill and there are 2 schools JJC and CSU. In addition to this, there's the cost per credit. So we can write out the following Matrix A, for the credits:
[tex]\begin{gathered} A=\begin{bmatrix}8 & 4 \\ 10 & 6 \\ 6 & 4\end{bmatrix}_{3\times2} \\ \begin{bmatrix}Sean \\ Kevin \\ Bill\end{bmatrix}=\begin{bmatrix}8 & 4 \\ 10 & 6 \\ 6 & 4\end{bmatrix}_{3\times2} \end{gathered}[/tex]Note that Matrix A, in this case, works as a table. On the Matrix on the left, we have the name of the students, and at Matrix A, we have each row the credits each student is taking.
2) So now:
[tex]B=\begin{bmatrix}103 & 249 \\ \end{bmatrix}_{1\times2}[/tex]Notice that we multiply A by B we'll get the cost for every student.
[tex]\begin{gathered} A=\begin{bmatrix}8 & 4 \\ 10 & 6 \\ 6 & 4\end{bmatrix}_{3\times2} \\ B=\begin{bmatrix}103 & 249 \\ \end{bmatrix}_{1\times2} \end{gathered}[/tex]And that is the answer.