XAT 2017 Question 59
This is a detailed step-by-step solution for XAT 2017 Question 59. Understand the concept, common mistakes, and expert tips to solve similar questions in XAT exam.
XAT
We have to employ the pigeon hole principle to solve this problem.
The maximum number of students who can be picked from each department such that 5 students are not selected from the same department is 4.
Therefore, after 4 students from each department are selected (i.e., 4*5 = 20 students in total), the 21st student selected will be the fifth student to be selected from one of the 5 departments. Therefore, 20+1 = 21 students should be selected in total to ensure that at least five students from one of the departments is selected. Therefore, option C is the right answer.