Consider the following premises. If Richard were excited, then Charles is an electrician. If Charles were an electrician, then it is overcast. If Richard were fast, then Richard is excited. It is not overcast. Can we infer the following from them? If we can, name the inference rule being used: Richard is not fast.
 From the fact that if Richard were excited, then Charles is an electrician, and that if Charles were an electrician, then it is overcast we can infer that if Richard were excited, then it is overcast via transitivity. From the fact that if Richard were fast, then Richard is excited, and that if Richard were excited, then it is overcast we can infer that if Richard were fast, then it is overcast via transitivity. Finally, from the fact that if Richard were fast, then it is overcast, and that it is not overcast we can infer that Richard is not fast via modus tollens. Therefore, the answer is yes.