99/10 as a mixed fraction

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters .

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”?

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?