A professor has recorded exam grades for 10 students in his class, but one of the grades is no longer readable. If the mean score on the exam was 80 and the mean of the 9 readable scores is 84, what is the value of the unreadable score?

The value of the unreadable score is 44.

Step-by-step explanation:

The mean is the sum of all the exams' scores divided by the number of exams. So

In which S is the sum of all the exams's scores and N is the number of exams.

In this problem, we have that:

10 students, so N = 10.

9 readable scores have a mean 84, there is also one unreadable score, so

Mean of 80, so M = 80.

We want to find x

The value of the unreadable score is 44.

v = 1/3 a^2h

step-by-step explanation:

the volume is 1/3 a^2h.