Consider the following premises. For all x_2, x_2 will work or x_2 is not happy. For all x_2, if x_2 works, then x_2 is a server. There is at least one x_2 for which if x_2 were a server, then x_2 is rich. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_2 for which if x_2 were happy, then x_2 is rich.
 From the fact that for all x_2, x_2 will work or x_2 is not happy we can infer that for all x_2, if x_2 were happy, then x_2 is working via universal rewriting. From the fact that for all x_2, if x_2 works, then x_2 is a server, and that there is at least one x_2 for which if x_2 were a server, then x_2 is rich we can infer that there is at least one x_2 for which if x_2 works, then x_2 is rich via existential transitivity. Finally, from the fact that for all x_2, if x_2 were happy, then x_2 is working, and that there is at least one x_2 for which if x_2 works, then x_2 is rich we can infer that there is at least one x_2 for which if x_2 were happy, then x_2 is rich via existential transitivity. Therefore, the answer is yes.