ExamBro
ExamBro
JEE Mains · Maths · STD 11 - 6. permutation and combination

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 \(..........\).

  1. A \(43\)
  2. B \(44\)
  3. C \(42\)
  4. D \(41\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(44\)

Step-by-step Solution

Detailed explanation

Derangement of \(5\) students \(D_5=5 !\left(1-\frac{1}{1 !}+\frac{1}{2 !}-\frac{1}{3 !}+\frac{1}{4 !}-\frac{1}{5 !}\right)\) \(=120\left(\frac{1}{2}-\frac{1}{6}+\frac{1}{24}-\frac{1}{120}\right)\) \(=60-20+5-1\) \(=40+4\) \(=44\)
Same subject
Explore more questions on app