Exam Scores An instructor gives a 100-point examination in which the grades are normally distributed. The mean is 75 and the standard deviation is 12. If there are 5% A's and 5% Fs, 15% B's and 15% D's, and 60% C's, find the scores that divide the distribution into those categories. Round the cutoff scores to the nearest whole number. Round intermediate z-value calculations to 2 decimal places. X C: D