Chapter 2, Problem 22RE

Job Earnings Sara, Quinn, Tamia, and Zack are working at the pool this summer. One week, they spend the following amounts of time at three different tasks:

$\begin{array}{l}\text{Concessions}\text{Front}\text{Desk}\text{Cleaning}\\ A=\left[\begin{array}{c}11\\ 9\\ 13\\ 13\end{array}\begin{array}{c}7\\ 5\\ 8\\ 7\end{array}\begin{array}{c}12\\ 16\\ 9\\ 10\end{array}\right]\begin{array}{c}\text{Sara}\\ \text{Quinn}\\ \text{Tamia}\\ \text{Zack}\end{array}\end{array}$

The hourly pay (in dollars) for the three different tasks is given by

$B=\left[\begin{array}{c}11\\ 9\\ 12\end{array}\right]\begin{array}{c}\text{Concessions}\\ \text{Front}\text{Desk}\\ \text{Cleaning}\end{array}$

(a) Calculate and interpret the matrix AB.

(b) Who earned the most that week? Who earned the least?

(c) If the hourly pay for concessions is changed to $12 and the hourly pay for cleaning is changed to $11, who earns the most that week?

(d) How many hours did Sara work that week?