Translate the following inference to logic notation: For all x, x_15 will take a plane or x_15 will not sleep. There is at least one x for which x_15 is a bartender if and only if x_15 will take a plane. For all x, x_15 will climb a mountain. For all x, if x_15 climbs a mountain, then x_15 is sleeping. Therefore there is at least one x for which x_15 is a bartender.
forall x: P(x) or ~Q(x). exists x: R(x) <-> P(x). forall x: S(x). forall x: S(x) -> Q(x). Therefore exists x: R(x).