Consider the following premises. For all x_12, x_12 is a musician. For all y_2, y_2 is happy and y_2 is a writer. Can we infer the following from them? There is at least one y_2 for which y_2 is happy.
 From the fact that for all y_2, y_2 is happy and y_2 is a writer we can infer that for all y_2, y_2 is happy. From the fact that for all x_12, x_12 is a musician we can infer that Jessica is a musician. From the fact that Jessica is a musician we can infer that there is at least one y_2 for which y_2 is a musician. From the fact that for all y_2, y_2 is happy, and that there is at least one y_2 for which y_2 is a musician we can infer that there is at least one y_2 for which y_2 is happy and y_2 is a musician. Finally, from the fact that there is at least one y_2 for which y_2 is happy and y_2 is a musician we can infer that there is at least one y_2 for which y_2 is happy. Therefore, the answer is yes.