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JEE Main 202427 JanuaryEvening Shift
Exam
JEE Main
Year
2024
Date
27 January
Shift
Evening Shift
Subject
Mathematics
Chapter
Permutation and Combination

JEE Main 2024 · 27 January · Evening Shift · Mathematics · Permutation and Combination

Let α = ( 4 ! ) ! ( 4 ! ) ^ 3 ! and β = ( 5 ! ) ! ( 5 ! ) ^ 4 ! ....

Let α=(4!)!(4!)3!\alpha = \dfrac{( 4 ! ) !}{( 4 ! {)}^{3 !}} and β=(5!)!(5!)4!\beta = \dfrac{( 5 ! ) !}{( 5 ! {)}^{4 !}}. Then :

Options

  1. Aα∈N\alpha \in N and β∉N\beta \notin N
  2. Bα∉N\alpha \notin N and β∈N\beta \in N
  3. Cα∈N\alpha \in N and β∈N\beta \in N
  4. Dα∉N\alpha \notin N and β∉N\beta \notin N

Correct answer

C. α∈N\alpha \in N and β∈N\beta \in N

Step-by-step solution

Given: α=(4!)!(4!)3!,β=(5!)!(5!)4!\alpha = \dfrac{( 4 ! ) !}{( 4 ! {)}^{3 !}}, \beta = \dfrac{( 5 ! ) !}{( 5 ! {)}^{4 !}}

⇒α=(24)!(4!)6,β=(120)!(5!)24⇒ \alpha = \dfrac{( 24 ) !}{( 4 ! {)}^{6}}, \beta = \dfrac{( 120 ) !}{( 5 ! {)}^{24}}

If 2424 distinct objects are divided into 66 groups of 44 objects in each group, then the number of ways of formation of group is=24!(4!)6.6!∈N= \dfrac{24 !}{( 4 ! {)}^{6} . 6 !} \in N

Similarly, let 120120 distinct objects are divided into 2424 groups of 55 objects in each group.

So, the number of ways of formation of groups

=(120)!(5!)24⋅24!∈N= \dfrac{( 120 ) !}{( 5 ! {)}^{24} \cdot 24 !} \in N

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