The function y= 2.85 + .55 (x - 1) can be used to determine the cost for a food delivery service of x miles. what is the rate of change of the function

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”?