Aretha had $0.85 in nickels and dimes. she has 2 more nickels than dimes. how many nickels and dimes does she have?

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”?