The grades on the midterm examination given in a

large managerial statistics class are normally distributed

with mean 75 and standard deviation 9. The

instructor of this class wants to assign an A grade to

the top 10% of the scores, a B grade to the next 10% of

the scores, a C grade to the next 10% of the scores, a

Dgrade to the next 10% of the scores, and an F grade

to all scores below the 60th percentile of this distribution.

For each possible letter grade, find the lowest

acceptable score within the established range. For

example, the lowest acceptable score for an A is the

score at the 90th percentile of this normal distribution.