Consider the following premises. Susan is sleeping if and only if it is late. Susan is sleeping or Thomas is a musician. It is late if and only if Karen is making tea. Karen is not making tea. Can we infer the following from them? If we can, name the inference rule being used: Thomas is a musician.
 From the fact that it is late if and only if Karen is making tea, and that Karen is not making tea we can infer that it is not late via biconditional elimination. From the fact that Susan is sleeping if and only if it is late, and that it is not late we can infer that Susan is not sleeping via biconditional elimination. Finally, from the fact that Susan is sleeping or Thomas is a musician, and that Susan is not sleeping we can infer that Thomas is a musician via disjunctive syllogism. Therefore, the answer is yes.