Consider the following premises. If Linda were an astronaut, then it is raining. If it rains, then David is a musician. Linda is an astronaut if and only if David is a musician. Can we infer the following from them? If we can, name the inference rule being used: David is a musician if and only if it is raining.
 From the fact that Linda is an astronaut if and only if David is a musician we can infer that if David were a musician, then Linda is an astronaut via biconditional elimination. From the fact that if David were a musician, then Linda is an astronaut, and that if Linda were an astronaut, then it is raining we can infer that if David were a musician, then it is raining via transitivity. Finally, from the fact that if David were a musician, then it is raining, and that if it rains, then David is a musician we can infer that David is a musician if and only if it is raining via biconditional introduction. Therefore, the answer is yes.