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