Translate the following inference to logic notation: For all x, z is a sailor if and only if z is a musician. There is at least one x for which z is a musician if and only if z will read a book. Therefore there is at least one x for which if z reads a book, then z is a sailor.
forall x: P(x) <-> Q(x). exists x: Q(x) <-> R(x). Therefore exists x: R(x) -> P(x).