Javier watched 2/5 of a movie. The entire length of the movie is x hours. He watched a total of 1 1/6 hours of the movie. To determine the total length of the movie, Javier wrote the equation shown below.

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”?