Consider the following premises. For all x_14, x_14 will work. For all x_14, x_14 is fast. If Sarah works, then it is snowing. Can we infer the following from them? If we can, name the inference rule being used: It is not snowing.
 From the fact that for all x_14, x_14 will work, and that for all x_14, x_14 is fast we can infer that for all x_14, x_14 will work and x_14 is fast via universal conjunction. From the fact that for all x_14, x_14 will work and x_14 is fast we can infer that for all x_14, x_14 will work via universal simplification. From the fact that for all x_14, x_14 will work we can infer that Sarah is working via universal instantiation. Finally, from the fact that if Sarah works, then it is snowing, and that Sarah is working we can infer that it is snowing via modus ponens, which contradicts that It is not snowing. Therefore, the answer is no.