A seamstress bought some some bolts of fabric at $25.30 each. She spent a total of $227.70. Write an equation and solve to find the number of bolts of fabric that she purchased.

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”?