Translate the following inference to logic notation: For all x, if x_5 reads a book, then x_5 is working. There is at least one x for which x_5 is fast if and only if x_5 will work. Therefore there is at least one x for which if x_5 reads a book, then x_5 is fast.
forall x: P(x) -> Q(x). exists x: R(x) <-> Q(x). Therefore exists x: P(x) -> R(x).