Consider the following premises. For all x_8, x_8 will drive a car if and only if x_8 will play tennis. For all x_8, x_8 is a sailor if and only if x_8 will drive a car. There is at least one x_8 for which x_8 will play tennis or x_8 is a sailor. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_8 for which x_8 will drive a car.
 From the fact that for all x_8, x_8 will drive a car if and only if x_8 will play tennis we can infer that for all x_8, if x_8 plays tennis, then x_8 is driving a car via universal biconditional elimination. From the fact that for all x_8, x_8 is a sailor if and only if x_8 will drive a car we can infer that for all x_8, if x_8 were a sailor, then x_8 is driving a car via universal biconditional elimination. Finally, from the fact that for all x_8, if x_8 plays tennis, then x_8 is driving a car, that for all x_8, if x_8 were a sailor, then x_8 is driving a car, and that there is at least one x_8 for which x_8 will play tennis or x_8 is a sailor we can infer that there is at least one x_8 for which x_8 will drive a car via existential disjunction elimination. Therefore, the answer is yes.