What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Susan plays squash, then Mary is poor. Susan is not playing squash. Mary is poor if and only if Susan is playing squash. If Jessica were a writer, then Mary is poor. If Mary were poor, then Jessica is a writer.
If Susan plays squash, then Jessica is a writer. Jessica is a writer if and only if Mary is poor. Mary is poor if and only if Jessica is a writer. If Mary were poor, then Susan is playing squash. If Susan plays squash, then Mary is poor. Mary is not poor.