Xavier Aptitude Test 2017 Paper

(c) For representation of minimum 5 students from atleast one department, assume that first 5 students are selected, one from each department.
Similarly, next 3 sets of 5 students will be selected (3 from each department). Now, 4 students are selected from each department. As soon as one more student is selected from any department, the representation of that department will be of 5 students. Hence, minimum 21 students should be in the committee.