Q. Mrs. Cooper asked her math class to keep track of their own grade. Michael, one of the students, lost his assignments, but he remembered the grades of 6 out of 8 assignments: 93, 65, 70, 68, 62 and 84. He also remembered that the mean of his grades for all 8 assignments was 73 and the other two assignments had identical grades. What were the grades on Michael's other two assignments?

Solution:

Let x be the grade for each of the two missing assignments. Since Michael knows the mean of all 8 assignments is 73, we have:

The missing grades were both 71.