Pedro took a bicycle ride as follows - he rode for 1.5 hours at a rate of r miles per hour

- he then increased that rate by 2 miles per hour and rode for 2.5 more hours

which equation can be used to determine the value of r ?

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”?