Consider the following premises. Robert is not playing tennis. Robert is playing tennis or Richard is not a cashier. Can we infer the following from them? If we can, name the inference rule being used: Richard is not a cashier.
 From the fact that Robert is playing tennis or Richard is not a cashier we can infer that if Richard were a cashier, then Robert is playing tennis via rewriting. Finally, from the fact that if Richard were a cashier, then Robert is playing tennis, and that Robert is not playing tennis we can infer that Richard is not a cashier via modus tollens. Therefore, the answer is yes.