Here are the correct Economic Principles for each scenario:
1. A swimmer prepares for an upcoming swim meet and is swimming laps. She has done 10 laps of 50 meters each and is feeling a bit tired. She is wondering if an additional 5 laps will help her.
**Answer: C. Thinking at the Margin**
2. A homeowner’s refrigerator is broken. He could try to fix it himself but feels it’s better to hire a professional repairman to do it.
**Answer: B.