Chapter 7.5, Problem 94E

a.

To determine

To find: the time spent exercising in a matrix.

Answer to Problem 94E

The matrix $A$ is $A=\left[\begin{array}{l}30\text{ 60 15}\\ \text{30 60 15}\end{array}\right]$ .

Explanation of Solution

Given information:

A 130-pound person and a 155-pound person bicycle for 30 minutes, jog for 15 minutes. And swim for 60 minutes.

Calculation: since, from the given information the matrix can be given as:

  $A=\left[\begin{array}{l}30\text{ 60 15}\\ \text{30 60 15}\end{array}\right]$

b.

To determine

To find: the value of $AB$ .

Answer to Problem 94E

The value of operation $AB$ is $\left[\begin{array}{l}29220\text{ 34800}\\ \text{29220 34800}\end{array}\right]$ .

Explanation of Solution

Given information :

  $A=\left[\begin{array}{l}30\text{ 60 15}\\ \text{30 60 15}\end{array}\right]$ , $B=\left[\begin{array}{l}325\text{ 387}\\ \text{236 281}\\ \text{354 422}\end{array}\right]$

Calculation : first find the value of $AB$ , multiply both matrices,

  $\begin{array}{l}AB=\left[\begin{array}{l}30\text{ 60 15}\\ \text{30 60 15}\end{array}\right]\left[\begin{array}{l}325\text{ 387}\\ \text{236 281}\\ \text{354 422}\end{array}\right]\\ AB=\left[\begin{array}{l}9750+14160+5310\text{ 11610+16860+6330}\\ \text{9750+14160+5310 11610+16860+6330}\end{array}\right]\\ AB=\left[\begin{array}{l}29220\text{ 34800}\\ \text{29220 34800}\end{array}\right]\end{array}$