Consider the following premises. It is overcast if and only if Jessica is a scientist. For all z, if z were a taxi driver, then z is running. Jessica is not a scientist. William is not running. Can we infer the following from them? If we can, name the inference rule being used: It is not overcast and William is not a taxi driver.
 From the fact that it is overcast if and only if Jessica is a scientist, and that Jessica is not a scientist we can infer that it is not overcast via biconditional elimination. From the fact that for all z, if z were a taxi driver, then z is running we can infer that if William were a taxi driver, then William is running via universal instantiation. From the fact that if William were a taxi driver, then William is running, and that William is not running we can infer that William is not a taxi driver via modus tollens. Finally, from the fact that it is not overcast, and that William is not a taxi driver we can infer that it is not overcast and William is not a taxi driver via conjunction. Therefore, the answer is yes.