Highly selective Backlog Qs for JEE MainMathematicsPermutation and Combination
If a polygon of n sides has 275 diagonals, then n is equal to
Options
- A25
- B35
- C20
- D15
Correct answer
A. 25
Step-by-step solution
A polygon of n sides has number of diagonals = n(n-3) 2 =275 (given) array cc & n^2-3 n-550=0 & n^2-25 n+22 n-550=0 & n(n-25)+22(n-25)=0 & (n-25)(n+22)=0 & n=25,( n=-22 is not possible ) array