Density of Unit Cells

Unit cell of a metal has edge length of $288 \mathrm{pm}$ and density of $7.86 \mathrm{g} {\mathrm{cm}}^{-3}$. Determine the type of crystal lattice. $[$Atomic mass of metal $56 \mathrm{g} {\mathrm{mol}}^{-1}]$

The density of silver having atomic mass $107.8 \mathrm{g} {\mathrm{mol}}^{-1}$ is $10.8 \mathrm{g} {\mathrm{cm}}^{-3}$ . If the edge length of cubic unit cell is $4.05\times {10}^{-8} \mathrm{cm}$ , find the number of silver atoms in the unit cell. $({\mathrm{N}}_{\mathrm{A}}=6.022\times {10}^{23}, 1 \mathrm{A} = {10}^{-8} \mathrm{cm})$