remo needs to buy a counter top for a bathroom he calculated the erea as 10 square feet the actual erea is 9.5 square feet what is remos percentage error

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”?