Consider the following premises. ~r_4 -> q. ~t. r_4 -> w_4. w_4 -> t. Can we infer q from them?
 From w_4 -> t, ~t we can infer ~w_4. From r_4 -> w_4, ~w_4 we can infer ~r_4. Finally, from ~r_4 -> q, ~r_4 we can infer q. Therefore, the answer is yes.