Mick paid $2.94 in sales tax on an item that cost $42.00 before tax. at that rate how much would he pay for an item that cost $58.00before tax

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”?