calories burned

[binomial20]

Your New Year's Resolution was to get back into shape. In order for you to do this, you want to burn 400 calories during 60 minutes of exercise per day. You've done your research and have found that you burn 8 calories per minute running and 3 calories per minute biking. How long should you spend doing each activity?

1. Define the variables in the problem.
2. Write an equation to describe the number of minutes biking and running.
3. Write an equation to describe the number of calories burned while biking and running.

 

[Denis]

You forgot to show your work.

 

[gayoc]

The 45 minutes multiplied to 8 calories of running give you 360 calories burned. And 3 calories per minute of biking multiplied to 15 minutes is 45 calories. All in all you’ve burned 405 calories in single hour.

calories

 

[mmm4444bot]

45 minutes times 8 calories of running is 360 calories burned. And 3 calories per minute of biking times 15 minutes is 45 calories. And, all in all you’ve burned 405 calories in a single hour.

This is true, but 405 is 5 more than the required number.

Your answer is incorrect for other reasons, too.

The posted exercise asks for definitions and a system of two equations. It does not ask for the system's solution.

Yet, I like your reasoning. You could use your minutes as approximations, and those approximations will serve as a check to see whether or not any solution to the system is "in the ballpark".