A metal crystallises into two cubic phases,face centred cubic (FCC) and body centred cubic (BCC),whose unit cell length are 3.5 and $3.0A^{\large\circ}$,respectively.Calculate the ratio of densities of FCC and BCC.

Question

$\begin{array}{1 1}1.36\\1.26\\1.46\\1.16\end{array} $