Your instructor decides to give the class one very hard exam question. The entire class may work together to answer the question since the instructor just wants the correct answer; she does not care how the class arrives at the answer or who contributes to answering the question. She will grade the final answer the class submits, and all students will receive the same grade. In one sense, the exam grade is a since all students will benefit and cannot be denied a grade, regardless of their individual contributions to answering the question.