Consider the following premises. For all x_12, x_12 will write a letter if and only if x_12 will make tea. It is late if and only if it is snowing. Jennifer is making tea if and only if it is snowing. It is not late. Can we infer the following from them? If we can, name the inference rule being used: Jennifer is not writing a letter.
 From the fact that for all x_12, x_12 will write a letter if and only if x_12 will make tea we can infer that Jennifer is writing a letter if and only if Jennifer is making tea via universal instantiation. From the fact that it is late if and only if it is snowing, and that it is not late we can infer that it is not snowing via biconditional elimination. From the fact that Jennifer is making tea if and only if it is snowing, and that it is not snowing we can infer that Jennifer is not making tea via biconditional elimination. Finally, from the fact that Jennifer is writing a letter if and only if Jennifer is making tea, and that Jennifer is not making tea we can infer that Jennifer is not writing a letter via biconditional elimination. Therefore, the answer is yes.