Consider the following premises. Mary is not a soldier. For all x_17, x_17 is a soldier or x_17 is bored. If David were a scientist, then Mary is not bored. David is a scientist if and only if James is making tea. Can we infer the following from them? If we can, name the inference rule being used: James is not making tea.
 From the fact that for all x_17, x_17 is a soldier or x_17 is bored we can infer that Mary is a soldier or Mary is bored via universal instantiation. From the fact that Mary is a soldier or Mary is bored, and that Mary is not a soldier we can infer that Mary is bored via disjunctive syllogism. From the fact that if David were a scientist, then Mary is not bored, and that Mary is bored we can infer that David is not a scientist via modus tollens. Finally, from the fact that David is a scientist if and only if James is making tea, and that David is not a scientist we can infer that James is not making tea via biconditional elimination. Therefore, the answer is yes.