Final averages are typically approximately normally distributed with a mean of 72 and a standard deviation of 12.5. Your professor says that the top 8% of the class will receive an A; the next 20%, a B; the next 42%, a C; the next 18%, a D; and the bottom 12%, an F.
a. What average must you exceed to obtain an A?
b. What average must you exceed to receive a grade better than a C?
c. What average must you obtain to pass the course? (You’ll need a D or better.)