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