Consider the following premises. If it snows, then Karen is playing squash. Karen is not playing squash. If Karen plays squash, then Richard is a musician. If Richard were a musician, then it is snowing. Can we infer the following from them? If we can, name the inference rule being used: Richard is a musician.
 From the fact that if Richard were a musician, then it is snowing, and that if it snows, then Karen is playing squash we can infer that if Richard were a musician, then Karen is playing squash via transitivity. From the fact that if Karen plays squash, then Richard is a musician, and that if Richard were a musician, then Karen is playing squash we can infer that Karen is playing squash if and only if Richard is a musician via biconditional introduction. Finally, from the fact that Karen is playing squash if and only if Richard is a musician, and that Karen is not playing squash we can infer that Richard is not a musician via biconditional elimination, which contradicts that Richard is a musician. Therefore, the answer is no.