Consider the following premises. If it is cold, then Jennifer is an electrician. If Jennifer were an electrician, then Barbara is reading a book. If Barbara reads a book, then it is cold. If Jennifer were an electrician, then it is cold. Can we infer the following from them? Jennifer is an electrician if and only if it is cold.
 From the fact that if Jennifer were an electrician, then Barbara is reading a book, and that if Barbara reads a book, then it is cold we can infer that if Jennifer were an electrician, then it is cold. From the fact that if it is cold, then Jennifer is an electrician, and that if Jennifer were an electrician, then it is cold we can infer that it is cold if and only if Jennifer is an electrician. From the fact that it is cold if and only if Jennifer is an electrician we can infer that if it is cold, then Jennifer is an electrician. Finally, from the fact that if Jennifer were an electrician, then it is cold, and that if it is cold, then Jennifer is an electrician we can infer that Jennifer is an electrician if and only if it is cold. Therefore, the answer is yes.