Translate the following inference to logic notation: For all x, if x_6 drives a car, then x_6 is a sailor. For all x, if x_6 writes a letter, then x_6 is a sailor. There is at least one x for which if x_6 were a sailor, then x_6 is writing a letter. Therefore there is at least one x for which if x_6 drives a car, then x_6 is writing a letter.
forall x: P(x) -> Q(x). forall x: R(x) -> Q(x). exists x: Q(x) -> R(x). Therefore exists x: P(x) -> R(x).