What is the percentage of void space in $hcp$ and $ccp$ structures (in $\%$)?

Element '$B$' forms $ccp$ structure and '$A$' occupies half of the octahedral voids,while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is

In a close-packed lattice,how does the size of an octahedral void compare to that of a tetrahedral void?

What is the percentage of empty space in a $bcc$ unit cell (in $\%$)?

Which of the following statements is not correct?

What is the total contribution of all corner particles in a $bcc$ unit cell?