Let $X \in \text{Random}(\mathbb{R})$ be a D3161: Random real number.
A D993: Real number $x \in \mathbb{R}$ is a percentile for $X$ with respect to $p \in [0, 1]$ if and only if

(1)	\begin{equation} \mathbb{P}(X \leq x) \geq p \end{equation}
(2)	\begin{equation} \mathbb{P}(X \geq x) \geq 1 - p \end{equation}