Consider the following premises. For all x_8, x_8 will not drink water. For all x_8, if x_8 drives a car, then x_8 is drinking water. For all x_8, x_8 will drive a car. Can we infer the following from them? If we can, name the inference rule being used: There is at least one y_2 for which y_2 is a sailor.
 From the fact that for all x_8, if x_8 drives a car, then x_8 is drinking water, and that for all x_8, x_8 will not drink water we can infer that for all x_8, x_8 will not drive a car via universal modus tollens. From the fact that for all x_8, x_8 will drive a car we can infer that for all x_8, x_8 will drive a car or x_8 is a sailor via universal addition. From the fact that for all x_8, x_8 will drive a car or x_8 is a sailor, and that for all x_8, x_8 will not drive a car we can infer that for all x_8, x_8 is a sailor via universal disjunctive syllogism. From the fact that for all x_8, x_8 is a sailor we can infer that Robert is a sailor via universal instantiation. Finally, from the fact that Robert is a sailor we can infer that there is at least one y_2 for which y_2 is a sailor via existential generalization. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.