What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it rains, then Mary is rich. If Mary were rich, then it is raining. Patricia is fast. If Mary were rich, then Patricia is not fast.
Mary is not rich. If it rains, then Patricia is not fast. It is raining if and only if Mary is rich. Mary is rich if and only if it is raining.