Translate the following inference to logic notation: There is at least one x for which if y_3 were a cashier, then y_3 is not working. For all x, y_3 will work. For all x, y_3 is a cashier if and only if y_3 will read a book. Therefore there is at least one x for which y_3 will not read a book.
exists x: P(x) -> ~Q(x). forall x: Q(x). forall x: P(x) <-> R(x). Therefore exists x: ~R(x).