Consider the following premises. For all x_15, x_15 will drive a car or x_15 is a lawyer. For all x_15, if x_15 were a lawyer, then x_15 is an artist. There is at least one x_15 for which x_15 will play tennis if and only if x_15 is a doctor. For all x_15, x_15 will not drive a car. For all x_15, if x_15 were an artist, then x_15 is playing tennis. Can we infer the following from them? There is at least one x_15 for which x_15 is a doctor.
 From the fact that for all x_15, if x_15 were a lawyer, then x_15 is an artist, and that for all x_15, if x_15 were an artist, then x_15 is playing tennis we can infer that for all x_15, if x_15 were a lawyer, then x_15 is playing tennis. From the fact that there is at least one x_15 for which x_15 will play tennis if and only if x_15 is a doctor we can infer that there is at least one x_15 for which if x_15 plays tennis, then x_15 is a doctor. From the fact that for all x_15, if x_15 were a lawyer, then x_15 is playing tennis, and that there is at least one x_15 for which if x_15 plays tennis, then x_15 is a doctor we can infer that there is at least one x_15 for which if x_15 were a lawyer, then x_15 is a doctor. From the fact that for all x_15, x_15 will drive a car or x_15 is a lawyer, and that for all x_15, x_15 will not drive a car we can infer that for all x_15, x_15 is a lawyer. Finally, from the fact that there is at least one x_15 for which if x_15 were a lawyer, then x_15 is a doctor, and that for all x_15, x_15 is a lawyer we can infer that there is at least one x_15 for which x_15 is a doctor. Therefore, the answer is yes.