Consider the following premises. If Thomas makes tea, then it is late. If it is late, then Thomas is making tea. If it is late, then Thomas is making tea. Can we infer the following from them? It is late if and only if Thomas is making tea.
 From the fact that if Thomas makes tea, then it is late, and that if it is late, then Thomas is making tea we can infer that Thomas is making tea if and only if it is late. From the fact that Thomas is making tea if and only if it is late we can infer that if Thomas makes tea, then it is late. Finally, from the fact that if it is late, then Thomas is making tea, and that if Thomas makes tea, then it is late we can infer that it is late if and only if Thomas is making tea. Therefore, the answer is yes.