Let $X \in \text{Random}[0, \infty]$ be a D5452: Random unsigned real number.
Let $\lambda > 0$ be a D993: Real number.
Let $\lambda > 0$ be a D993: Real number.
Then
\begin{equation}
\mathbb{P}(X \geq \lambda)
\leq \frac{1}{\lambda} \mathbb{E}(X)
\end{equation}