Consider the following premises. q -> p. w -> q. q -> w. w. p_4 -> p. Can we infer p from them?
 From q -> w, w -> q we can infer q <-> w. From q <-> w we can infer w -> q. From w -> q, q -> p we can infer w -> p. From w we can infer w or p_4. Finally, from w -> p, p_4 -> p, w or p_4 we can infer p. Therefore, the answer is yes.