Consider the following premises. If it is cloudy, then it is sunny. It is late. It is late if and only if it is sunny. 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 late we can infer that it is late or it is cloudy via addition. From the fact that it is late if and only if it is sunny we can infer that if it is late, then it is sunny via biconditional elimination. Finally, from the fact that if it is late, then it is sunny, that if it is cloudy, then it is sunny, and that it is late or it is cloudy we can infer that it is sunny via disjunction elimination. Therefore, the answer is yes.