Question

woman works out by running and swimming. When she runs, she burns 7 calories per minute. When she swims, she burns 8 calories per minute. She wants to burn at least 336 calories in her workout. Write an inequality that describes the situation. Let x represent the number of minutes running and y the number of minutes swimming. Because x and y must be positive, limit the boarders to quadrant I only.

Answer 1

An inequality to model this would be

7x + 8y ≥ 336.

We multiply the number of minutes running, x, by the number of calories burned each minute by running, 7.  We multiply the number of minutes swimming, y, by the number of calories burned each minute by swimming, 8.  Adding these together, it needs to be greater than or equal to 336, since she wants to burn at least that many calories.