Answer:
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
[tex]M = \frac{S}{N}[/tex]
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 [tex]S = 9*84 + x = 756 + x[/tex]
Mean of 80, so M = 80.
We want to find x
[tex]M = \frac{S}{N}[/tex]
[tex]80 = \frac{756+x}{10}[/tex]
[tex]800 = 756 + x[/tex]
[tex]x = 44[/tex]
The value of the unreadable score is 44.
