SOLUTION: A professor has found that the grades on a Statistics Exam are normally distributed with mean 72 and a standard deviation of 12. If only the best 15 % of the grades in the class w

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Question 1033456: A professor has found that the grades on a Statistics Exam are normally distributed with mean 72 and
a standard deviation of 12. If only the best 15 % of the grades in the class will get an A, what grade
must a student get in order to get an A?
I got as far as 15%=15/100=.15
1-.15=.85
and I got stuck. plz help me

Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
We need to find alpha such that
P%28X+%3E=+alpha%29+=+0.15
<==>
==> %28alpha+-+72%29%2F12+=+1.035
==> alpha+=+84.42