Consider the following premises. For all x_3, x_3 is not curious or x_3 will write a letter. For all x_3, x_3 is curious. There is at least one x_3 for which x_3 is not a mechanic or x_3 is an artist. Can we infer the following from them? There is at least one x_3 for which x_3 will write a letter or x_3 is an artist.
 From the fact that for all x_3, x_3 is curious we can infer that for all x_3, x_3 is curious or x_3 is a mechanic. From the fact that for all x_3, x_3 is curious or x_3 is a mechanic, and that for all x_3, x_3 is not curious or x_3 will write a letter we can infer that for all x_3, x_3 is a mechanic or x_3 will write a letter. Finally, from the fact that for all x_3, x_3 is a mechanic or x_3 will write a letter, and that there is at least one x_3 for which x_3 is not a mechanic or x_3 is an artist we can infer that there is at least one x_3 for which x_3 will write a letter or x_3 is an artist. Therefore, the answer is yes.