What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is late if and only if James is poor. Sarah is not sleeping. If William climbs a mountain, then Barbara is driving a car. Sarah is sleeping if and only if it is late. If James were not poor, then Barbara is driving a car.
If it is late, then James is poor. If Sarah sleeps, then it is late. If James were poor, then it is late. If it is late, then Sarah is sleeping. It is not late.