Consider the following premises. For all z_2, if z_2 were poor, then z_2 is a janitor. William is making tea. If William makes tea, then John is a janitor. Can we infer the following from them? John is not a janitor.
 From the fact that for all z_2, if z_2 were poor, then z_2 is a janitor we can infer that if John were poor, then John is a janitor. From the fact that William is making tea we can infer that William is making tea or John is poor. Finally, from the fact that if William makes tea, then John is a janitor, that if John were poor, then John is a janitor, and that William is making tea or John is poor we can infer that John is a janitor, which contradicts that John is not a janitor. Therefore, the answer is no.