Question

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 84​, what is the value of the unreadable​ score?

Answer 1

64

Explanation:

`mean=(sum\ of\ total\ number\ of\ score)/(total\ number\ of\ students)`

we have given that mean of 9 students is 84

so total score of 9 students = mean×9

=84×9=756

and we have given mean score of exam is 82 and there is total 10 students so the total score of 10 students =10×82

=820

so the unreadable score = score of 10 students -score of 9 students =820-756=64