Consider the following premises. If Robert takes a plane, then Linda is working. If Linda works, then Robert is taking a plane. Robert is not taking a plane. David is writing a letter. Can we infer the following from them? David is writing a letter and Linda is not working.
 From the fact that if Robert takes a plane, then Linda is working, and that if Linda works, then Robert is taking a plane we can infer that Robert is taking a plane if and only if Linda is working. From the fact that Robert is taking a plane if and only if Linda is working, and that Robert is not taking a plane we can infer that Linda is not working. Finally, from the fact that David is writing a letter, and that Linda is not working we can infer that David is writing a letter and Linda is not working. Therefore, the answer is yes.