Consider the following premises. If Charles were poor, then Charles is an electrician. For all x_11, x_11 is poor if and only if x_11 is an electrician. Charles is not poor. Can we infer the following from them? Charles is an electrician.
 From the fact that for all x_11, x_11 is poor if and only if x_11 is an electrician we can infer that for all x_11, if x_11 were an electrician, then x_11 is poor. From the fact that for all x_11, if x_11 were an electrician, then x_11 is poor we can infer that if Charles were an electrician, then Charles is poor. From the fact that if Charles were an electrician, then Charles is poor, and that if Charles were poor, then Charles is an electrician we can infer that Charles is an electrician if and only if Charles is poor. Finally, from the fact that Charles is an electrician if and only if Charles is poor, and that Charles is not poor we can infer that Charles is not an electrician, which contradicts that Charles is an electrician. Therefore, the answer is no.