Question

Calculate the value of $\frac{Z}{10}.$ where
Z = Co-ordination number of 2D-square close packing
+
Co-ordination number of 2D-hcp
+
Co-ordination number of 3D-square close packing
+
Co-ordination number of 3D, ABCABC..........Packing
+
Co-ordination number of 3D, ABAB...........packing

Answer 1

$Z=4+6+6+12+12=40$
$\frac{Z}{10}=\frac{40}{10}=4$