Five students are selected from n students such that the ratio of number of ways in which 2 particular students are selected to the number of ways 2 particular students not selected is 2: 3 . Then the value of n is

Step-by-step solution

Five students are selected from n students. Number of ways in which 2 particular students are sélected = n ⁻² C ₃ Number of ways in which 2 particular students are not selected = ^ n -2 C ₅ According to the given condition, ^ n-2 C₃ ^ n-2 C₅ = 2 3 aligned & ( n -2) ! 3 !( n -5) ! 5 !( n -7) ! ( n -2) ! = 2 3 & ( n -5)( n -6)=30 & n =11 aligned