Consider the following premises. Richard is happy. Barbara is not an office clerk. Joseph is a janitor if and only if Barbara is an office clerk. If Linda were a server, then Richard is not happy. Can we infer the following from them? If we can, name the inference rule being used: Linda is a server.
 From the fact that Joseph is a janitor if and only if Barbara is an office clerk, and that Barbara is not an office clerk we can infer that Joseph is not a janitor via biconditional elimination. Finally, from the fact that if Linda were a server, then Richard is not happy, and that Richard is happy we can infer that Linda is not a server via modus tollens, which contradicts that Linda is a server. Therefore, the answer is no.