Consider the following premises. If Susan were a musician, then Jennifer is a taxi driver. Susan is a musician if and only if Jennifer is a taxi driver. Can we infer the following from them? If we can, name the inference rule being used: If is not true that Jennifer is a taxi driver if and only if Susan is a musician.
 From the fact that Susan is a musician if and only if Jennifer is a taxi driver we can infer that if Jennifer were a taxi driver, then Susan is a musician via biconditional elimination. Finally, from the fact that if Jennifer were a taxi driver, then Susan is a musician, and that if Susan were a musician, then Jennifer is a taxi driver we can infer that Jennifer is a taxi driver if and only if Susan is a musician via biconditional introduction, which contradicts that If is not true that Jennifer is a taxi driver if and only if Susan is a musician. Therefore, the answer is no.