Using the Empirical Rule, it is found that 68% of the cars driven by the students at Chillville have gas mileages between 24.0 and 32.0 miles per gallon.
It states that, for a normally distributed random variable:
In this problem, considering the mean of 28 mpg and the standard deviation of 4 mpg, we have that 24.0 and 32.0 mpg is within 1 standard deviation of the mean, hence the percentage is of 68%.
More can be learned about the Empirical Rule at https://brainly.com/question/24537145