Consider the following premises. For all x_18, x_18 is a scientist if and only if x_18 will cook. For all x_18, x_18 will not cook. For all x_18, x_18 is a scientist or x_18 will go running. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_1 for which x_1 will go running or x_1 will make tea.
 From the fact that for all x_18, x_18 is a scientist if and only if x_18 will cook, and that for all x_18, x_18 will not cook we can infer that for all x_18, x_18 is not a scientist via universal biconditional elimination. From the fact that for all x_18, x_18 is a scientist or x_18 will go running, and that for all x_18, x_18 is not a scientist we can infer that for all x_18, x_18 will go running via universal disjunctive syllogism. From the fact that for all x_18, x_18 will go running we can infer that James is running via universal instantiation. From the fact that James is running we can infer that there is at least one x_1 for which x_1 will go running via existential generalization. Finally, from the fact that there is at least one x_1 for which x_1 will go running we can infer that there is at least one x_1 for which x_1 will go running or x_1 will make tea via existential addition. Therefore, the answer is yes.