Translate the following inference to logic notation: For all x, y is curious. There is at least one x for which y will drink water if and only if y is curious. For all x, if y takes a plane, then y is drinking water. Therefore there is at least one x for which y will drink water.
forall x: P(x). exists x: Q(x) <-> P(x). forall x: R(x) -> Q(x). Therefore exists x: Q(x).