Which transformer turns ratio is needed to match two 16-ohm parallel devices to an output of 22.2 ohms?

ANS:D - 0.60:1

Formula of relation between the primary and secondary:
((Np)^2)(Zp)=((Ns)^2)(Zs).

Since the primary (Zp) has two 16-ohm parallel it would result to 8-ohms in total (Zp = 8ohms).

Substituting through trial and error given by choices:

((1)^2)(8)=((0.6)^2)(22.2).
8 = 0.60 * 0.60 * 22.2.
8 = 7.992.