Consider the following premises. For all z_3, if z_3 were rich, then z_3 is making tea. For all z_3, z_3 will make tea if and only if z_3 is rich. Can we infer the following from them? For all z_3, z_3 is rich if and only if z_3 will make tea.
 From the fact that for all z_3, z_3 will make tea if and only if z_3 is rich we can infer that for all z_3, if z_3 makes tea, then z_3 is rich. Finally, from the fact that for all z_3, if z_3 were rich, then z_3 is making tea, and that for all z_3, if z_3 makes tea, then z_3 is rich we can infer that for all z_3, z_3 is rich if and only if z_3 will make tea. Therefore, the answer is yes.