NTA Abhyas JEE Main2020MathematicsPermutation and CombinationPractice
The inequality C n + 1 6 + C n 4 > C n + 2 5 − C n 5 holds true for all n greater than
Options
- A8
- B9
- C7
- D1
Correct answer
B. 9
Step-by-step solution
C n + 1 6 + C n 4 + C n 5 > C n + 2 5 ⇒ C n + 1 6 + C n + 1 5 > C n + 2 5 ⇒ C n + 2 6 > C n + 2 5 ⇒ n + 2 ! 6 ! n - 4 ! > n + 2 ! 5 ! n - 3 ! ⇒ 1 6 > 1 n - 3 ⇒ n - 3 > 6 ⇒ n > 9