In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 9. grades are to be assigned according to the following rule:
the top 10% receive a's. the next 20% receive b's. the middle 40% receive c's. the next 20% received d's. the bottom 10% receive f's. what is the least amount of points that a student must score, on the final exam, in order to earn a c? (round your answer to two decimal places.)
the answer is 72?