Translate the following inference to logic notation: If Charles were not a sailor, then David is a police officer. It is windy. For all x, x_20 is a sailor if and only if x_20 will play tennis. Charles is not playing tennis. Therefore it is windy and David is a police officer.
~P(a) -> p. q. forall x: P(x) <-> Q(x). ~Q(a). Therefore q and p.