Let we have two qubits A and B. First qubit has eigenstates |A0> and |A1>, and second has |B0> and |B1>.
Let them be in the entangled state, described with vector
c1 * |A0> * |B0> + c2 * |B0> * |B1>|
where c1 and c2 are complex numbers with |c1|^2 + |c2|^2 = 1.
Then what is density...