Which of the following exponential regression equations best fits the data shown below A. y = 8.46•3.51^x B. y = 10.84•1.77^x C. y = 5.32•2.23^x
D. y = 3.14•4.98^x

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”?