Should've studied (Part 1)

Ken thought it was a bad idea when his sister suggested it. She was failing a class, and asked him to swap bodies with her since he had aced the course when he took it. In hindsight, he probably should have studied. He had taken the class five years ago and had forgotten everything. As he waited for his sister to arrive so they could swap back, he pondered how to break the news that he likely failed...