Consider the following premises. For all x_13, if x_13 works, then x_13 is running. There is at least one x_13 for which x_13 is a nurse. For all x_13, if x_13 goes running, then x_13 is happy. For all x_13, x_13 will go running if and only if x_13 is happy. For all x_13, x_13 will work or x_13 is happy. Can we infer the following from them? There is at least one x_13 for which x_13 will go running and x_13 is a nurse.
 From the fact that for all x_13, x_13 will go running if and only if x_13 is happy we can infer that for all x_13, if x_13 were happy, then x_13 is running. From the fact that for all x_13, if x_13 goes running, then x_13 is happy, and that for all x_13, if x_13 were happy, then x_13 is running we can infer that for all x_13, x_13 will go running if and only if x_13 is happy. From the fact that for all x_13, x_13 will go running if and only if x_13 is happy we can infer that for all x_13, if x_13 were happy, then x_13 is running. From the fact that for all x_13, if x_13 works, then x_13 is running, that for all x_13, if x_13 were happy, then x_13 is running, and that for all x_13, x_13 will work or x_13 is happy we can infer that for all x_13, x_13 will go running. Finally, from the fact that for all x_13, x_13 will go running, and that there is at least one x_13 for which x_13 is a nurse we can infer that there is at least one x_13 for which x_13 will go running and x_13 is a nurse. Therefore, the answer is yes.