Consider the following premises. If William writes a letter, then Sarah is cooking. If Sarah cooks, then it is cold. It is not cold. Michael is taking a plane. Can we infer the following from them? If we can, name the inference rule being used: William is writing a letter.
 From the fact that if Sarah cooks, then it is cold, and that it is not cold we can infer that Sarah is not cooking via modus tollens. Finally, from the fact that if William writes a letter, then Sarah is cooking, and that Sarah is not cooking we can infer that William is not writing a letter via modus tollens, which contradicts that William is writing a letter. Therefore, the answer is no.