What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Barbara were a sailor, then David is a musician. If Charles listens to a song, then Barbara is a sailor. David is not a musician. Sarah is not an artist. Barbara is playing squash if and only if Sarah is an artist.
Barbara is not a sailor. David is not a musician and Sarah is not an artist. Sarah is not an artist and David is not a musician. If Barbara plays squash, then Sarah is an artist. If Sarah were an artist, then Barbara is playing squash. Barbara is not playing squash.