Let Pn denotes the no. of ways of selecting 3 people out of 'n' sitting in a row if no two of them are
consecutive and Qn is the corresponding figure when they are in circle .
If Pn - Qn = 6 , then 'n' is equal to:
The Attempt at a Solution
Pn = (n-2) C 3
Qn = (n-3) C 3
But I am getting wrong answer.
Please tell which one is wrong Pn or Qn .