In an examination hall there are ' \(m n\) ' chairs in \(m\) rows and \(n\) columns. The number of ways in…

In an examination hall there are ' \(m n\) ' chairs in \(m\) rows and \(n\) columns. The number of ways in which \(m\) students can be seated such that no row is vacant is
  1. \(m^n n\) !
  2. \(n^m m\) !
  3. \(m^m n !\)
  4. \(n^n m\) !

Solution

Given that these is ' \(m n\) ' chairs in \(m\) rows and \(n\) columns.
\(\therefore\) Number of ways in which one student can seat in Ist column \(=n\) So, similarly \(m\) students can seat in \(n^m\) ways. Since, students can be arranged in \(m\) ! ways, \(\therefore\) Total number of ways \(=m ! \times n^m\) ways

Asked in: AP EAMCET 2019 (22 Apr Shift 1)

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