Consider the following premises. Mary is a nurse if and only if Patricia is poor. Barbara is rich. If it snows, then Patricia is poor. It is snowing or Mary is a nurse. Can we infer the following from them? If we can, name the inference rule being used: Patricia is poor and Barbara is rich.
 From the fact that Mary is a nurse if and only if Patricia is poor we can infer that if Mary were a nurse, then Patricia is poor via biconditional elimination. From the fact that if it snows, then Patricia is poor, that if Mary were a nurse, then Patricia is poor, and that it is snowing or Mary is a nurse we can infer that Patricia is poor via disjunction elimination. Finally, from the fact that Patricia is poor, and that Barbara is rich we can infer that Patricia is poor and Barbara is rich via conjunction. Therefore, the answer is yes.