a student’s grade in a class is simply the mean of five 100-point
exams
a. If the student has grades of 77, 73, 97, and 89 on the first four exams, what is the
students’ grade before taking the last exam?
b. What is the lowest score that the student can earn on the last exam to get an B (80) in the
course?
(77 + 73 + 97 + 89)/4 = ?
(77 + 73 + 97 + 89 + x)/5 = 80
To calculate the student's current grade before taking the last exam, you need to find the mean (average) of the first four exam scores.
a. Given the grades of 77, 73, 97, and 89 on the first four exams, you can calculate the mean as follows:
Mean = (77 + 73 + 97 + 89) / 4
= 336 / 4
= 84
Therefore, the student's grade before taking the last exam is 84.
b. To determine the lowest score the student can earn on the last exam to get a B (80) in the course, you need to solve for the last exam score.
Let's call the last exam score "x".
To calculate the course grade, you need to find the mean of all five exam scores, including the last exam.
Mean = (77 + 73 + 97 + 89 + x) / 5
The mean should be equal to 80 to achieve a B in the course. Therefore, you can set up the equation as:
80 = (77 + 73 + 97 + 89 + x) / 5
Now, solve for x:
400 = 336 + x
400 - 336 = x
64 = x
Hence, the lowest score the student can earn on the last exam to get a B (80) in the course is 64.