Consider the following premises. John is not a sailor. For all x_17, x_17 is poor if and only if x_17 is a sailor. Can we infer the following from them? John is not poor or it is windy.
 From the fact that for all x_17, x_17 is poor if and only if x_17 is a sailor we can infer that for all x_17, if x_17 were poor, then x_17 is a sailor. From the fact that for all x_17, if x_17 were poor, then x_17 is a sailor we can infer that if John were poor, then John is a sailor. From the fact that if John were poor, then John is a sailor, and that John is not a sailor we can infer that John is not poor. Finally, from the fact that John is not poor we can infer that John is not poor or it is windy. Therefore, the answer is yes.