Consider the following premises. If Elisabeth writes a letter, then Michael is drinking water. If Michael drinks water, then Elisabeth is a mechanic. For all x_14, x_14 is a mechanic if and only if x_14 will write a letter. Can we infer the following from them? If we can, name the inference rule being used: If Elisabeth writes a letter, then Elisabeth is a mechanic.
 From the fact that for all x_14, x_14 is a mechanic if and only if x_14 will write a letter we can infer that Elisabeth is a mechanic if and only if Elisabeth is writing a letter via universal instantiation. Finally, from the fact that if Elisabeth writes a letter, then Michael is drinking water, and that if Michael drinks water, then Elisabeth is a mechanic we can infer that if Elisabeth writes a letter, then Elisabeth is a mechanic via transitivity. Therefore, the answer is yes.