Given X∼Poisson(λ=3)X \sim \text{Poisson}(\lambda=3)X∼Poisson(λ=3), what is the conditional probability P(X=1∣X≤1)P(X=1 | X \leq 1)P(X=1∣X≤1)?
\frac{3e^{-3}}{1+3e^{-3}}
\frac{3}{1+3}
\frac{3}{1+4}
\frac{3e^{-3}}{e^{-3}(1+3)}