Consider the following premises. t_2 <-> q. ~q -> t. p_15 <-> t_2. ~p_15. s_2 -> t. Can we infer t from them?
 From t_2 <-> q we can infer q -> t_2. From p_15 <-> t_2, ~p_15 we can infer ~t_2. From q -> t_2, ~t_2 we can infer ~q. From ~q we can infer ~q or s_2. Finally, from ~q -> t, s_2 -> t, ~q or s_2 we can infer t. Therefore, the answer is yes.