Consider the following premises. For all z, z will listen to a song. For all z, z will listen to a song if and only if z will play squash. Can we infer the following from them? If we can, name the inference rule being used: Michael is playing squash or Robert is a police officer.
 From the fact that for all z, z will listen to a song if and only if z will play squash we can infer that for all z, if z listens to a song, then z is playing squash via universal biconditional elimination. From the fact that for all z, if z listens to a song, then z is playing squash, and that for all z, z will listen to a song we can infer that for all z, z will play squash via universal modus ponens. From the fact that for all z, z will play squash we can infer that Michael is playing squash via universal instantiation. Finally, from the fact that Michael is playing squash we can infer that Michael is playing squash or Robert is a police officer via addition. Therefore, the answer is yes.