What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, if z listens to a song, then z is happy. There is at least one z for which if z were a cashier, then z is listening to a song. For all z, z is not a cashier. For all z, if z were happy, then z is a cashier.
For all z, z is not happy. For all z, if z listens to a song, then z is a cashier. There is at least one z for which if z were a cashier, then z is happy. There is at least one z for which if z were happy, then z is listening to a song.