Question:

5 students seated in 5 allotted seats. Number of ways none sits on allotted seat is

None

1 way

2 ways

4 ways

Step-by-Step Solution

Key Concept: Derangement of 5: $D_5=5!(1-1+\frac{1}{2!}-\frac{1}{3!}+\frac{1}{4!}-\frac{1}{5!})$.

$D_5=44$.

Correct Answer: 44