WAEC Mathematics 2015 Theory — Question 10

Model answer

(i) Draw a universal set U (the school). Within it, draw set A (General Arts class students) as a larger circle, and set B (good Literature students) as a smaller circle entirely inside A, showing that every good Literature student is a General Arts student. (ii) (b)(i) 'Vivian is in General Arts therefore she is a good Literature student' - INVALID, since being in General Arts does not guarantee being a good Literature student (the class could contain both good and bad Literature students). (ii) 'Audu is not a good Literature student therefore he is not in General Arts class' - also INVALID, for the same reason. (iii) 'Kweku is not in the General Arts class therefore he is not a good Literature student' - VALID, since all good Literature students must be in General Arts; if Kweku is not in General Arts, he cannot be a good Literature student.