Translate the following inference to logic notation: There is at least one x for which x_15 is a mechanic if and only if x_15 will play squash. For all x, if x_15 were a mechanic, then x_15 is reading a book. For all x, x_15 will play squash if and only if x_15 will read a book. Therefore there is at least one x for which if x_15 were a mechanic, then x_15 is playing squash.
exists x: P(x) <-> Q(x). forall x: P(x) -> R(x). forall x: Q(x) <-> R(x). Therefore exists x: P(x) -> Q(x).