Consider the following premises. If Richard makes tea, then Patricia is a writer. Richard is not making tea. If Patricia were a writer, then Richard is making tea. Patricia is a writer if and only if it is late. Can we infer the following from them? It is not late.
 From the fact that if Patricia were a writer, then Richard is making tea, and that if Richard makes tea, then Patricia is a writer we can infer that Patricia is a writer if and only if Richard is making tea. From the fact that Patricia is a writer if and only if Richard is making tea, and that Richard is not making tea we can infer that Patricia is not a writer. Finally, from the fact that Patricia is a writer if and only if it is late, and that Patricia is not a writer we can infer that it is not late. Therefore, the answer is yes.