Darnell charges $10 per hour for his babysitting service. Jordan charges an initial fee of $4 to show up and then an additional $9 per hour while babysitting. A In the boxes below, enter a system of equations that represent the amount of money that Darnell and Jordan charge.

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”?