What is the total number of atoms present in an $fcc$ unit cell?

In a face centred cubic lattice,atom $A$ occupies the corner positions and atom $B$ occupies the face centre positions. If one atom of $B$ is missing from one of the face centred points,the formula of the compound is:

An ionic compound has unit cells consisting of $A$ ions at the corners of a cube and $B$ ions on the centres of the faces of the cube. The empirical formula of this compound is

What is the coordination number of $Zn$ in the crystal structure of $Zn$?

Total volume of atoms present in a face-centred cubic unit cell of a metal is ($r$ is atomic radius)

The $8:8$ type packing is present in which of the following?