The illinoian stage began about 300,000 years ago. The wallstonian began about 352,000 years ago. Compare 300,000 to 352,000

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”?