Consider the following premises. Richard is sad and it is overcast. If Michael works, then Richard is not sad. Can we infer the following from them? If we can, name the inference rule being used: Michael is not working.
 From the fact that Richard is sad and it is overcast we can infer that Richard is sad via simplification. Finally, from the fact that if Michael works, then Richard is not sad, and that Richard is sad we can infer that Michael is not working via modus tollens. Therefore, the answer is yes.