Consider the following premises. If Richard were a soldier, then it is cloudy. If it is cloudy, then Richard is making tea. For all z_3, if z_3 makes tea, then z_3 is a soldier. Can we infer the following from them? If we can, name the inference rule being used: Richard is making tea if and only if it is cloudy.
 From the fact that for all z_3, if z_3 makes tea, then z_3 is a soldier we can infer that if Richard makes tea, then Richard is a soldier via universal instantiation. From the fact that if Richard makes tea, then Richard is a soldier, and that if Richard were a soldier, then it is cloudy we can infer that if Richard makes tea, then it is cloudy via transitivity. Finally, from the fact that if Richard makes tea, then it is cloudy, and that if it is cloudy, then Richard is making tea we can infer that Richard is making tea if and only if it is cloudy via biconditional introduction. Therefore, the answer is yes.