Consider the following premises. w_4 -> s. ~s. p_4 -> q. ~q. Can we infer ~w_4 and ~p_4 from them? If possible, name the inference rules being used at each step.
 From p_4 -> q, ~q we can infer ~p_4 via modus tollens. From w_4 -> s, ~s we can infer ~w_4 via modus tollens. Finally, from ~w_4, ~p_4 we can infer ~w_4 and ~p_4 via conjunction. Therefore, the answer is yes.