Consider the following premises. For all x_10, if x_10 reads a book, then x_10 is an office clerk. There is at least one x_10 for which if x_10 were fast, then x_10 is an electrician. For all x_10, x_10 will read a book. For all x_10, x_10 is an electrician if and only if x_10 is an office clerk. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_10 for which x_10 is an electrician.
 From the fact that for all x_10, x_10 is an electrician if and only if x_10 is an office clerk we can infer that for all x_10, if x_10 were an office clerk, then x_10 is an electrician via universal biconditional elimination. From the fact that for all x_10, x_10 will read a book we can infer that for all x_10, x_10 will read a book or x_10 is fast via universal addition. From the fact that for all x_10, if x_10 reads a book, then x_10 is an office clerk, and that for all x_10, if x_10 were an office clerk, then x_10 is an electrician we can infer that for all x_10, if x_10 reads a book, then x_10 is an electrician via universal transitivity. Finally, from the fact that for all x_10, if x_10 reads a book, then x_10 is an electrician, that there is at least one x_10 for which if x_10 were fast, then x_10 is an electrician, and that for all x_10, x_10 will read a book or x_10 is fast we can infer that there is at least one x_10 for which x_10 is an electrician via existential disjunction elimination. Therefore, the answer is yes.