Consider the following premises. Michael is not drinking water. It is sunny if and only if Michael is drinking water. Mary is sleeping. Can we infer the following from them? If we can, name the inference rule being used: It is sunny.
 From the fact that it is sunny if and only if Michael is drinking water we can infer that if it is sunny, then Michael is drinking water via biconditional elimination. Finally, from the fact that if it is sunny, then Michael is drinking water, and that Michael is not drinking water we can infer that it is not sunny via modus tollens, which contradicts that It is sunny. Therefore, the answer is no.