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 82 and the mean of the 9 readable scores is 86, what is the value of the unreadable score?

The mean of a data-set is given by the sum of all values in the data-set divided by the number of values.
This data-set has 10 values.
This data-set has mean 82.
The 9 readable scores have mean of 86, thus they add up to: [tex]S_9 = 9 \times 86 = 774[/tex].
The unreadable score is x.

Applying the mean:

[tex]\frac{774 + x}{10} = 82[/tex]

[tex]774 + x = 820[/tex]

[tex]x = 820 - 774[/tex]

[tex]x = 46[/tex]

The value of the unreadable score is 46.

A similar problem is given at https://brainly.com/question/22056321

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 82 and the mean of the 9 readable scores is 86​, what is the value of the unreadable​ score?