Translate the following inference to logic notation: For all x, x_4 is rich or x_4 is not a taxi driver. There is at least one x for which if x_4 climbs a mountain, then x_4 is rich. For all x, x_4 is a taxi driver. Therefore there is at least one x for which x_4 is rich.
forall x: P(x) or ~Q(x). exists x: R(x) -> P(x). forall x: Q(x). Therefore exists x: P(x).