MHT CET202120 Sep 2021Evening ShiftMathematicsPermutation and CombinationActual
If n ! 2 !( n -2) ! and n ! 4 !( n -4) ! are in the ratio 2: 1 , then n =
Options
- A6
- B4
- C5
- D3
Correct answer
C. 5
Step-by-step solution
We have n ! 2 !(n-2) ! 4 !(n-4) ! n ! = 2 1 (4 3) (n-2)(n-3) =2 n^2-5 n+6=6