Consider the following premises. It is not cold. If it is late, then Robert is making tea. If Robert makes tea, then it is cloudy. It is cold 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 late.
 From the fact that it is cold if and only if it is cloudy, and that it is not cold we can infer that it is not cloudy via biconditional elimination. From the fact that if Robert makes tea, then it is cloudy, and that it is not cloudy we can infer that Robert is not making tea via modus tollens. Finally, from the fact that if it is late, then Robert is making tea, and that Robert is not making tea we can infer that it is not late via modus tollens, which contradicts that It is late. Therefore, the answer is no.