250 students in a high school senior class are surveyed about what majors they intend to declare in college. Of the 250 students, 100 plan to major in mathematics, 80 plan to major in computer science, and 20 plan to pursue a double major in mathematics and computer science. Using this information, answer each of the following questions. Let M be the event that a randomly selected student plans to major in mathematics and CCC be the event that a randomly selected student plans to major in computer science.