Translate the following inference to logic notation: For all x, if x_12 were a sailor, then x_12 is a cashier. For all x, if x_12 were a mechanic, then x_12 is a sailor. There is at least one x for which x_12 is a mechanic. For all x, if x_12 were fast, then x_12 is not a cashier. Therefore there is at least one x for which x_12 is not fast.
forall x: P(x) -> Q(x). forall x: R(x) -> P(x). exists x: R(x). forall x: S(x) -> ~Q(x). Therefore exists x: ~S(x).