What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Richard is cooking. It is not late. For all x_23, if x_23 cooks, then x_23 is a doctor. It is late if and only if Sarah is running.
Richard is cooking and it is not late. It is not late and Richard is cooking. If it is late, then Sarah is running. If Sarah goes running, then it is late. Sarah is not running. There is at least one x for which x will cook.