Consider the following premises. For all x_5, x_5 is a nurse. For all x_5, x_5 is a mechanic. For all x_5, if x_5 were a nurse, then x_5 is fast. Can we infer the following from them? For all x_5, x_5 is fast.
 From the fact that for all x_5, x_5 is a nurse, and that for all x_5, x_5 is a mechanic we can infer that for all x_5, x_5 is a nurse and x_5 is a mechanic. From the fact that for all x_5, x_5 is a nurse and x_5 is a mechanic we can infer that for all x_5, x_5 is a nurse. Finally, from the fact that for all x_5, if x_5 were a nurse, then x_5 is fast, and that for all x_5, x_5 is a nurse we can infer that for all x_5, x_5 is fast. Therefore, the answer is yes.