If $A$ and $B$ are two square matrices with $\operatorname{det} A=5$ and $\operatorname{det}\left(B^T \cdot…
If $A$ and $B$ are two square matrices with $\operatorname{det} A=5$ and $\operatorname{det}\left(B^T \cdot A^T\right)=-15$, then $\operatorname{det} B$ is equal to