The number of active cases of a certain virus, $N$, can be modeled by the equation $N=C(3{)}^{kt}$, where $C$ and $k$ are constants, and $t$ is the number of weeks since the initial observation. Initially, there are 50 active cases. After 2 weeks, the number of active cases has grown to 450.

Based on this model, what is the predicted number of active cases after 3 weeks?