Consider the following premises. For all x_5, x_5 is a doctor if and only if x_5 is an artist. For all x_5, if x_5 works, then x_5 is a doctor. There is at least one x_5 for which x_5 will work. Can we infer the following from them? There is at least one x_5 for which x_5 is a doctor.
 From the fact that there is at least one x_5 for which x_5 will work we can infer that there is at least one x_5 for which x_5 will work or x_5 is an artist. From the fact that for all x_5, x_5 is a doctor if and only if x_5 is an artist we can infer that for all x_5, if x_5 were an artist, then x_5 is a doctor. Finally, from the fact that for all x_5, if x_5 works, then x_5 is a doctor, that for all x_5, if x_5 were an artist, then x_5 is a doctor, and that there is at least one x_5 for which x_5 will work or x_5 is an artist we can infer that there is at least one x_5 for which x_5 is a doctor. Therefore, the answer is yes.