Consider the following premises. John is not listening to a song. If it is cold, then John is a taxi driver. It is cold if and only if Susan is an electrician. If John were a taxi driver, then it is cold. John is listening to a song if and only if John is a taxi driver. Can we infer the following from them? If we can, name the inference rule being used: Susan is an electrician.
 From the fact that if it is cold, then John is a taxi driver, and that if John were a taxi driver, then it is cold we can infer that it is cold if and only if John is a taxi driver via biconditional introduction. From the fact that John is listening to a song if and only if John is a taxi driver, and that John is not listening to a song we can infer that John is not a taxi driver via biconditional elimination. From the fact that it is cold if and only if John is a taxi driver, and that John is not a taxi driver we can infer that it is not cold via biconditional elimination. Finally, from the fact that it is cold if and only if Susan is an electrician, and that it is not cold we can infer that Susan is not an electrician via biconditional elimination, which contradicts that Susan is an electrician. Therefore, the answer is no.