Consider the following premises. Joseph is excited or Robert is playing tennis. Susan is a doctor if and only if Charles is taking a plane. Susan is not a doctor. If Joseph were excited, then Charles is taking a plane. Can we infer the following from them? If we can, name the inference rule being used: Robert is not playing tennis.
 From the fact that Susan is a doctor if and only if Charles is taking a plane, and that Susan is not a doctor we can infer that Charles is not taking a plane via biconditional elimination. From the fact that if Joseph were excited, then Charles is taking a plane, and that Charles is not taking a plane we can infer that Joseph is not excited via modus tollens. Finally, from the fact that Joseph is excited or Robert is playing tennis, and that Joseph is not excited we can infer that Robert is playing tennis via disjunctive syllogism, which contradicts that Robert is not playing tennis. Therefore, the answer is no.