Consider the following premises. Sarah is not excited. Sarah is excited if and only if Richard is cooking. Richard is cooking or it is late. Can we infer the following from them? If we can, name the inference rule being used: Patricia is sad or it is late.
 From the fact that Sarah is excited if and only if Richard is cooking, and that Sarah is not excited we can infer that Richard is not cooking via biconditional elimination. From the fact that Richard is not cooking we can infer that Richard is not cooking or Patricia is sad via addition. Finally, from the fact that Richard is not cooking or Patricia is sad, and that Richard is cooking or it is late we can infer that Patricia is sad or it is late via resolution. Therefore, the answer is yes.