Consider the following premises. It is raining or Robert is not working. If it is windy, then it is raining. Thomas is a janitor if and only if it is windy. Robert is working or Thomas is a janitor. Can we infer the following from them? It is raining.
 From the fact that Thomas is a janitor if and only if it is windy we can infer that if Thomas were a janitor, then it is windy. From the fact that it is raining or Robert is not working we can infer that if Robert works, then it is raining. From the fact that if Thomas were a janitor, then it is windy, and that if it is windy, then it is raining we can infer that if Thomas were a janitor, then it is raining. Finally, from the fact that if Robert works, then it is raining, that if Thomas were a janitor, then it is raining, and that Robert is working or Thomas is a janitor we can infer that it is raining. Therefore, the answer is yes.