Let $\{N(t) : t \geq 0\}$ be a Poisson process with rate $λ$, and $Z$ represent the number of arrivals in the interval of time $[0,t]$. Let $T$ be a random variable, exponentially distributed with parameter $µ > 0$, independent of $N(t)$. Determine the distribution of the number of arrivals $Z$, happening in the random interval of time $[0,T]$.
Any hints?