Consider the following premises. It is sunny if and only if it is overcast. If Sarah were an electrician, then it is sunny. Sarah is an electrician if and only if Sarah is an astronaut. It is not overcast. Can we infer the following from them? If we can, name the inference rule being used: Sarah is not an astronaut.
 From the fact that it is sunny if and only if it is overcast, and that it is not overcast we can infer that it is not sunny via biconditional elimination. From the fact that if Sarah were an electrician, then it is sunny, and that it is not sunny we can infer that Sarah is not an electrician via modus tollens. Finally, from the fact that Sarah is an electrician if and only if Sarah is an astronaut, and that Sarah is not an electrician we can infer that Sarah is not an astronaut via biconditional elimination. Therefore, the answer is yes.