Explain what probability is

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”?

How much higher is checkpoint 4 than checkpoint 2 if checkpoint 4 is -143 and checkpoint 2 is -182

Point q is located at (-4, 6). point r is located at (8,6). what is the distance from point q to point r