Consider the following premises. For all x_7, x_7 is not a doctor or x_7 will go running. There is at least one x_7 for which x_7 will take a plane if and only if x_7 is a musician. For all x_7, x_7 is a doctor or x_7 is a musician. For all x_7, if x_7 goes running, then x_7 is taking a plane. Can we infer the following from them? There is at least one x_7 for which x_7 will take a plane.
 From the fact that for all x_7, x_7 is a doctor or x_7 is a musician, and that for all x_7, x_7 is not a doctor or x_7 will go running we can infer that for all x_7, x_7 is a musician or x_7 will go running. From the fact that there is at least one x_7 for which x_7 will take a plane if and only if x_7 is a musician we can infer that there is at least one x_7 for which if x_7 were a musician, then x_7 is taking a plane. Finally, from the fact that there is at least one x_7 for which if x_7 were a musician, then x_7 is taking a plane, that for all x_7, if x_7 goes running, then x_7 is taking a plane, and that for all x_7, x_7 is a musician or x_7 will go running we can infer that there is at least one x_7 for which x_7 will take a plane. Therefore, the answer is yes.