Multiply a matrix by a scalar
\(D\) is a matrix recording the number of hours each employee of a bakery is rostered at each of its shops in one week
In the matrix, the rows are Ashley, Blake (top to bottom) and the columns are City shop, River shop (left to right)
\[D = \begin{bmatrix} 5 & 12 \\ 12 & 3 \end{bmatrix}\]
The roster for a fortnight is exactly two of these weeks in a row, so every figure in the table doubles