Consider the following premises. For all z, z is a sailor if and only if z will play squash. Jennifer is bored or it is windy. Jennifer is bored if and only if Thomas is playing squash. For all z, z is a sailor if and only if z will work. For all z, z will not work. Can we infer the following from them? If we can, name the inference rule being used: It is not windy.
 From the fact that for all z, z is a sailor if and only if z will work, and that for all z, z will not work we can infer that for all z, z is not a sailor via universal biconditional elimination. From the fact that for all z, z is a sailor if and only if z will play squash, and that for all z, z is not a sailor we can infer that for all z, z will not play squash via universal biconditional elimination. From the fact that for all z, z will not play squash we can infer that Thomas is not playing squash via universal instantiation. From the fact that Jennifer is bored if and only if Thomas is playing squash, and that Thomas is not playing squash we can infer that Jennifer is not bored via biconditional elimination. Finally, from the fact that Jennifer is bored or it is windy, and that Jennifer is not bored we can infer that it is windy via disjunctive syllogism, which contradicts that It is not windy. Therefore, the answer is no.