Let $E$ and $F$ be two events.
- If $E$ and $F$ are independent events, then we have
\begin{equation*}
P(E\mbox{ and }F) = P(E)\times P(F)
\end{equation*} - If $E$ and $F$ are dependent events, then we have
\begin{equation*}
P(E\mbox{ and } F) = P(E) \times P(F|E),
\end{equation*}
where $F|E$ denotes the event that $F$ occurs after occurring $E$.
