Consider the following premises. If Barbara sleeps, then Robert is not bored. Michael is not taking a plane. Robert is bored. For all x_11, x_11 is an office clerk if and only if x_11 will take a plane. Can we infer the following from them? If we can, name the inference rule being used: Michael is an office clerk.
 From the fact that if Barbara sleeps, then Robert is not bored, and that Robert is bored we can infer that Barbara is not sleeping via modus tollens. From the fact that for all x_11, x_11 is an office clerk if and only if x_11 will take a plane we can infer that Michael is an office clerk if and only if Michael is taking a plane via universal instantiation. Finally, from the fact that Michael is an office clerk if and only if Michael is taking a plane, and that Michael is not taking a plane we can infer that Michael is not an office clerk via biconditional elimination, which contradicts that Michael is an office clerk. Therefore, the answer is no.