Let p number of triangles |Permutations and Combinations| JEEMAIN2025

JEE MAIN_2025

070425_S2

Question

Let $p$ be the number of all triangles that can be formed by joining the vertices of a regular polygon $P$ of $n$ sides and $q$ be the number of all quadrilaterals that can be formed by joining the vertices of $P$. If $p+q=126$, then the eccentricity of the ellipse $\frac{x^2}{16}+\frac{y^2}{n}=1$ is:

Select the correct option:

$\frac{\sqrt{7}}{4}$

$\frac{1}{2}$

$\frac{1}{\sqrt{2}}$

$\frac{3}{4}$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution