Gabrielle's age is three times Mikhail's age. The sum of their ages is 20 . What is Mikhail's age?

3. solve the given inequality and graph the solution on a number line.

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”?

What’s the range cuz i can’t find it?