If $P$ be any point on the ellipse $16x^2 + 25y^2 = 400$ with foci $S$ and $S'$ and area of $\triangle PSS'$ is 9 square units, then the abscissa of point $P$ is...........

The value of $\lim\limits_{n \to \infty}\left[\dfrac{1}{1 - n^2} + \dfrac{2}{1 - n^2} + \ldots + \dfrac{n}{1 - n^2}\right]^3$ is

If $\sim p \vee q$ is false then which of the following is correct?

The contrapositive of $\sim q \rightarrow p$ is equivalent to