Explanation:
In the first scenario, because of being the only student in the class my efforts to produce good grades will be low and inefficient since I believe there is no one competing with me for good grades.
However, in the second scenario of a class of 40 students, there will be great competition to be that 1 student to get a good grade as mentioned by the teacher. Changes will be seen in my efforts at study and paying attention in class, as well as asking questions about the subject in order to get a good grade.