Consider the following premises. It is snowing if and only if it is late. Robert is poor if and only if it is snowing. Robert is not poor. If William were a musician, then it is late. Can we infer the following from them? William is not a musician.
 From the fact that Robert is poor if and only if it is snowing we can infer that if it snows, then Robert is poor. From the fact that it is snowing if and only if it is late we can infer that if it is late, then it is snowing. From the fact that if William were a musician, then it is late, and that if it is late, then it is snowing we can infer that if William were a musician, then it is snowing. From the fact that if William were a musician, then it is snowing, and that if it snows, then Robert is poor we can infer that if William were a musician, then Robert is poor. Finally, from the fact that if William were a musician, then Robert is poor, and that Robert is not poor we can infer that William is not a musician. Therefore, the answer is yes.