Consider the following premises. If Richard were a poet, then it is late. It is late if and only if Richard is a poet. For all z, if z were a poet, then z is running. Can we infer the following from them? If we can, name the inference rule being used: If it is late, then Richard is running.
 From the fact that for all z, if z were a poet, then z is running we can infer that if Richard were a poet, then Richard is running via universal instantiation. From the fact that it is late if and only if Richard is a poet we can infer that if it is late, then Richard is a poet via biconditional elimination. From the fact that if Richard were a poet, then it is late, and that if it is late, then Richard is a poet we can infer that Richard is a poet if and only if it is late via biconditional introduction. From the fact that Richard is a poet if and only if it is late we can infer that if it is late, then Richard is a poet via biconditional elimination. Finally, from the fact that if it is late, then Richard is a poet, and that if Richard were a poet, then Richard is running we can infer that if it is late, then Richard is running via transitivity. Therefore, the answer is yes.