Consider the following premises. q_10 -> r. p_10 <-> q_10. r -> p_10. Can we infer p_10 -> r from them? If possible, name the inference rules being used at each step.
 From p_10 <-> q_10 we can infer p_10 -> q_10 via biconditional elimination. Finally, from p_10 -> q_10, q_10 -> r we can infer p_10 -> r via transitivity. Therefore, the answer is yes.