Consider the following premises. For all z, z is not an electrician. For all z, z will drink water if and only if z will play squash. For all z, if z were an electrician, then z is drinking water. For all z, if z drinks water, then z is an electrician. Charles is playing squash or Mary is a lawyer. Can we infer the following from them? If we can, name the inference rule being used: Charles is playing squash or Mary is a lawyer.
That is one of the premises. Therefore, the answer is yes.