Suppose a video store charges nonmembers $4 to rent each video . a store membership costs $21 and members pay only $2.50 to rent each video. for what number of videos is the cost of the same?

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”?