Consider the following premises. Barbara is playing a game or Mary is not a lawyer. If Barbara plays a game, then it is windy. Mary is a lawyer or it is not windy. Can we infer the following from them? It is windy if and only if Mary is a lawyer.
 From the fact that Barbara is playing a game or Mary is not a lawyer we can infer that if Mary were a lawyer, then Barbara is playing a game. From the fact that Mary is a lawyer or it is not windy we can infer that if it is windy, then Mary is a lawyer. From the fact that if Mary were a lawyer, then Barbara is playing a game, and that if Barbara plays a game, then it is windy we can infer that if Mary were a lawyer, then it is windy. Finally, from the fact that if it is windy, then Mary is a lawyer, and that if Mary were a lawyer, then it is windy we can infer that it is windy if and only if Mary is a lawyer. Therefore, the answer is yes.