A professor at a local university noted that the grades of her students were normally distributed with a mean of 78 and a standard deviation of 10

a. The professor has informed us that 16.6 percent of her students received grades of A. What is the minimum score needed to receive a grade of A?
b. If 12.1 percent of her students failed the course and received F's, what was the maximum score among those who received an F?
c. If 33 percent of the students received grades of B or better (i.e., A's and B's), what is the minimum score of those who received a B?

a. 87.7
b. 66.3
c. 82.4