What is the number of octahedral voids present in 0.2 mol of a compound forming hcp structure?

What is the percentage atom economy when formula weight of product obtained is 70 u and the sum of formula weight of reactant is 140 u ?

$$\int \frac{x \mathrm{~d} x}{(x-1)^2(x+2)}=$$

Let $Z$ be a complex number such that $|Z|+Z=2+i$ (where $i=\sqrt{-1})$, then $|Z|$ is equal to