Consider the following premises. p_4 <-> q. p_4 -> t. Can we infer q -> t from them? If possible, name the inference rules being used at each step.
 From p_4 <-> q we can infer q -> p_4 via biconditional elimination. Finally, from q -> p_4, p_4 -> t we can infer q -> t via transitivity. Therefore, the answer is yes.