Translate the following inference to logic notation: For all x, x_11 will write a letter or x_11 is a mechanic. For all x, x_11 will not write a letter. There is at least one x for which if x_11 were a mechanic, then x_11 is taking a plane. For all x, if x_11 climbs a mountain, then x_11 is not taking a plane. Therefore there is at least one x for which x_11 will not climb a mountain.
forall x: P(x) or Q(x). forall x: ~P(x). exists x: Q(x) -> R(x). forall x: S(x) -> ~R(x). Therefore exists x: ~S(x).