Consider the following premises. Richard is not fast. Richard is fast if and only if Thomas is drinking water. Thomas is drinking water if and only if it is cloudy. Can we infer the following from them? If we can, name the inference rule being used: It is not cloudy or Linda is running.
 From the fact that Richard is fast if and only if Thomas is drinking water, and that Richard is not fast we can infer that Thomas is not drinking water via biconditional elimination. From the fact that Thomas is drinking water if and only if it is cloudy we can infer that if it is cloudy, then Thomas is drinking water via biconditional elimination. From the fact that if it is cloudy, then Thomas is drinking water, and that Thomas is not drinking water we can infer that it is not cloudy via modus tollens. Finally, from the fact that it is not cloudy we can infer that it is not cloudy or Linda is running via addition. Therefore, the answer is yes.