Consider the following premises. For all x_3, x_3 is not a janitor. There is at least one x_3 for which if x_3 were an astronaut, then x_3 is a janitor. For all x_3, x_3 is an astronaut. Can we infer the following from them? There is at least one x_3 for which x_3 is a bartender.
 From the fact that there is at least one x_3 for which if x_3 were an astronaut, then x_3 is a janitor, and that for all x_3, x_3 is not a janitor we can infer that there is at least one x_3 for which x_3 is not an astronaut. From the fact that for all x_3, x_3 is an astronaut we can infer that for all x_3, x_3 is an astronaut or x_3 is a bartender. Finally, from the fact that for all x_3, x_3 is an astronaut or x_3 is a bartender, and that there is at least one x_3 for which x_3 is not an astronaut we can infer that there is at least one x_3 for which x_3 is a bartender. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.