Translate the following inference to logic notation: If Susan climbs a mountain, then Robert is playing a game. James is playing squash if and only if Joseph is taking a plane. If Robert plays a game, then Mary is drinking water. If Joseph doesn't take a plane, then Susan is climbing a mountain. James is not playing squash. Therefore Mary is drinking water.
p -> q. r <-> s. q -> t. ~s -> p. ~r. Therefore t.