A metropolitan school system consists of three districts—north, south, and central. The north district contains 25% of all students, the south district contains 40%, and the central district contains...

A metropolitan school system consists of three districts—north, south, and central. The north district
contains 25% of all students, the south district contains 40%, and the central district contains
35%. A minimum-competency test was given to all students; 10% of the north district students
failed, 15% of the south district students failed, and 5% of the central district students failed. Develop a joint probability table.