Consider the following premises. For all x_3, x_3 is a musician or x_3 will work. There is at least one x_3 for which if x_3 works, then x_3 is running. For all x_3, x_3 is a musician if and only if x_3 will go running. Can we infer the following from them? There is at least one x_3 for which x_3 will go running.
 From the fact that for all x_3, x_3 is a musician if and only if x_3 will go running we can infer that for all x_3, if x_3 were a musician, then x_3 is running. Finally, from the fact that for all x_3, if x_3 were a musician, then x_3 is running, that there is at least one x_3 for which if x_3 works, then x_3 is running, and that for all x_3, x_3 is a musician or x_3 will work we can infer that there is at least one x_3 for which x_3 will go running. Therefore, the answer is yes.