Consider the following premises. For all x_4, x_4 is a carpenter. For all x_4, if x_4 were a carpenter, then x_4 is playing a game. For all x_4, x_4 will take a plane. Can we infer the following from them? If we can, name the inference rule being used: Charles is taking a plane.
 From the fact that for all x_4, if x_4 were a carpenter, then x_4 is playing a game, and that for all x_4, x_4 is a carpenter we can infer that for all x_4, x_4 will play a game via universal modus ponens. From the fact that for all x_4, x_4 will take a plane, and that for all x_4, x_4 will play a game we can infer that for all x_4, x_4 will take a plane and x_4 will play a game via universal conjunction. From the fact that for all x_4, x_4 will take a plane and x_4 will play a game we can infer that Charles is taking a plane and Charles is playing a game via universal instantiation. Finally, from the fact that Charles is taking a plane and Charles is playing a game we can infer that Charles is taking a plane via simplification. Therefore, the answer is yes.