What is the probability of getting a red marble first, a white marble second, and a blue marble third if none of the selelcted marbles are returned to the jar additional marbles are drawn? (Enter your probability as a fraction.)

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?