Chapter 2.3, Problem 65E

Wardrobe costs The quantities of pants, shirts, and jackets owned by Mike and Don are given by the matrix A, and the costs of these items are given by matrix B.

$\begin{array}{l}\begin{array}{ccc}\text{Pants}& \text{Shirts}& \text{Jackets}\end{array}\\ \begin{array}{c}\text{Mike}\\ \text{Don}\end{array}\left[\begin{array}{c}6\\ 2\end{array}\begin{array}{c}8\\ 5\end{array}\begin{array}{c}2\\ 3\end{array}\right]=A\end{array}$

$\begin{array}{l}\text{Cost}\\ \begin{array}{c}\text{Pants}\\ \text{Shirts}\\ \text{Jackets}\end{array}\left[\begin{array}{c}20\\ 15\\ 50\end{array}\right]=B\end{array}$

(a) Calculate the matrix AB.

(b) Interpret the entries of the matrix AB.

(c) Calculate the matrix 1.25B.

(d) Interpret the entries of the matrix 1.25B.