What is the coordination number of a one-dimensional close-packed arrangement?

In a solid,$B^{-}$ ions occupy corners of a cube forming $ccp$ structure. If $A^{+}$ ions occupy half the tetrahedral voids,the formula of the solid is:

$A$ solid contains elements $A$ and $B$. Anions of $B$ form $ccp$ lattice. Cations of $A$ occupy $50 \%$ of octahedral voids and $50 \%$ of tetrahedral voids. What is the molecular formula of the solid?

For a simple cubic $(SC)$,body-centered cubic $(BCC)$,and face-centered cubic $(FCC)$ unit cell with edge length $a$,what is the ratio of the radii of the atoms present in them?

An ionic solid is $HCP$ of $B^{2-}$ ions and $A^{x+}$ ions are in one-fourth of tetrahedral voids. The value of $x$ should be

The molecular formula of a crystal is $AB_2O_4$. Oxygen atoms form $ccp$ lattice. Atoms of $A$ occupy $x \%$ of tetrahedral voids and atoms of $B$ occupy $y \%$ of octahedral voids. $x$ and $y$ are respectively: