Consider the following premises. For all z, z is not a musician. For all z, z will make tea if and only if z is a musician. For all z, z is fast if and only if z will make tea. Can we infer the following from them? If we can, name the inference rule being used: For all z, z is not fast.
 From the fact that for all z, z is fast if and only if z will make tea we can infer that for all z, if z were fast, then z is making tea via universal biconditional elimination. From the fact that for all z, z will make tea if and only if z is a musician, and that for all z, z is not a musician we can infer that for all z, z will not make tea via universal biconditional elimination. Finally, from the fact that for all z, if z were fast, then z is making tea, and that for all z, z will not make tea we can infer that for all z, z is not fast via universal modus tollens. Therefore, the answer is yes.