Translate the following inference to logic notation: For all x, x_6 will drive a car or x_6 is a cashier. There is at least one x for which x_6 will drive a car if and only if x_6 will read a book. For all x, if x_6 were a cashier, then x_6 is working. For all x, if x_6 works, then x_6 is reading a book. Therefore there is at least one x for which x_6 will read a book.
forall x: P(x) or Q(x). exists x: P(x) <-> R(x). forall x: Q(x) -> S(x). forall x: S(x) -> R(x). Therefore exists x: R(x).