Sixty percent of the students at Scandia Tech drive to class

Sixty percent of the students at Scandia Tech drive to class and 30 percent have GPAs of at least 3.00. Ten percent of the students have a 3.00 GPA and drive to class. If we select a student at random, what is the likelihood that the student had a 3.00 or drives to class?

Solution

60% just drive to class
30% just have a 3.00
10% both drive to class and have a 3.00
P(student had a 3.00 or drives to class) = 60+30-10=80%