You can use a graphing calculator to solve a system of three equations.
Multiple Choice On a new exercise program, your friend plans to do a run-jog-walk routine every other day for 40 min. She would like to burn 310 calories during each session. The table shows how many calories a person your friend's age and weight burns per minute of each type of exercise.
Running (8 mi/h) | Jogging (5 mi/h) | Walking (3.5 mi/h) |
12.5 cal/min | 7.5 cal/min | 3.5 cal/min |
If your friend plans on jogging twice as long as she runs, how many minutes should she exercise at each rate?
Step 1 Define the variables.
Let x = number of minutes running.
y = number of minutes jogging.
z = number of minutes walking.
Step 2 Write a system of equations for the problem.
How many equations do you need to solve this problem?
Since there are three variables you need three equations.
Step 3 Write the system as a matrix equation.
Step 5 Interpret the solution.
Your friend should run for 10 min, jog for 20 min, and walk for 10 min.
The correct answer is D.