Consider the following premises. If Linda plays a game, then Sarah is a police officer. It is not late. If Sarah were a police officer, then Linda is playing a game. It is late if and only if Linda is playing a game. Can we infer the following from them? If we can, name the inference rule being used: Sarah is not a police officer.
 From the fact that if Linda plays a game, then Sarah is a police officer, and that if Sarah were a police officer, then Linda is playing a game we can infer that Linda is playing a game if and only if Sarah is a police officer via biconditional introduction. From the fact that it is late if and only if Linda is playing a game, and that it is not late we can infer that Linda is not playing a game via biconditional elimination. Finally, from the fact that Linda is playing a game if and only if Sarah is a police officer, and that Linda is not playing a game we can infer that Sarah is not a police officer via biconditional elimination. Therefore, the answer is yes.