In an examination, 5 students have been allotted their seats as per their roll numbers. The number of ways, in which none of the students sits on the allotted seat, is

Step-by-step solution

5 boys with allotted roll numbers and seat numbers are seated in such a way that no one sits on the allotted seats. The number of ways of such seating arrangement is equal to the derangement of 5 boys i.e., = 5 ! 1 - 1 1 ! + 1 2 ! - 1 3 ! + 1 4 ! - 1 5 ! = 5 ! - 5 ! + 60 - 20 + 5 - 1 = 44