Consider the following premises. For all x_15, x_15 will take a plane or x_15 is an electrician. For all x_15, if x_15 reads a book, then x_15 is running. For all x_15, if x_15 takes a plane, then x_15 is a janitor. For all x_15, x_15 will read a book if and only if x_15 is a janitor. For all x_15, x_15 is an electrician if and only if x_15 is a janitor. Can we infer the following from them? If we can, name the inference rule being used: For all x_15, x_15 will go running.
 From the fact that for all x_15, x_15 is an electrician if and only if x_15 is a janitor we can infer that for all x_15, if x_15 were an electrician, then x_15 is a janitor via universal biconditional elimination. From the fact that for all x_15, if x_15 takes a plane, then x_15 is a janitor, that for all x_15, if x_15 were an electrician, then x_15 is a janitor, and that for all x_15, x_15 will take a plane or x_15 is an electrician we can infer that for all x_15, x_15 is a janitor via universal disjunction elimination. From the fact that for all x_15, x_15 will read a book if and only if x_15 is a janitor we can infer that for all x_15, if x_15 were a janitor, then x_15 is reading a book via universal biconditional elimination. From the fact that for all x_15, if x_15 were a janitor, then x_15 is reading a book, and that for all x_15, if x_15 reads a book, then x_15 is running we can infer that for all x_15, if x_15 were a janitor, then x_15 is running via universal transitivity. Finally, from the fact that for all x_15, if x_15 were a janitor, then x_15 is running, and that for all x_15, x_15 is a janitor we can infer that for all x_15, x_15 will go running via universal modus ponens. Therefore, the answer is yes.