Translate the following inference to logic notation: For all x, z_2 will play squash if and only if z_2 will climb a mountain. There is at least one x for which z_2 will play squash. Therefore there is at least one x for which z_2 will climb a mountain.
forall x: P(x) <-> Q(x). exists x: P(x). Therefore exists x: Q(x).