Consider the following premises. For all x_9, x_9 will take a plane if and only if x_9 is a carpenter. For all x_9, x_9 will play tennis. For all x_9, if x_9 plays tennis, then x_9 is a carpenter. There is at least one x_9 for which if x_9 were a carpenter, then x_9 is a bartender. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_9 for which x_9 is a bartender.
 From the fact that for all x_9, x_9 will play tennis we can infer that for all x_9, x_9 will play tennis or x_9 will take a plane via universal addition. From the fact that for all x_9, x_9 will take a plane if and only if x_9 is a carpenter we can infer that for all x_9, if x_9 takes a plane, then x_9 is a carpenter via universal biconditional elimination. From the fact that for all x_9, if x_9 plays tennis, then x_9 is a carpenter, that for all x_9, if x_9 takes a plane, then x_9 is a carpenter, and that for all x_9, x_9 will play tennis or x_9 will take a plane we can infer that for all x_9, x_9 is a carpenter via universal disjunction elimination. Finally, from the fact that there is at least one x_9 for which if x_9 were a carpenter, then x_9 is a bartender, and that for all x_9, x_9 is a carpenter we can infer that there is at least one x_9 for which x_9 is a bartender via existential modus ponens. Therefore, the answer is yes.