Consider the following premises. It is late if and only if Jennifer is a server. Jennifer is not a server. It is late. Can we infer the following from them? Karen is taking a plane.
 From the fact that it is late if and only if Jennifer is a server, and that Jennifer is not a server we can infer that it is not late. From the fact that it is not late we can infer that it is not late or Karen is taking a plane. Finally, from the fact that it is not late or Karen is taking a plane, and that it is late we can infer that Karen is taking a plane. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.