Consider the following premises. For all y_1, y_1 will go running. Linda is playing tennis if and only if Jennifer is running. Can we infer the following from them? Linda is playing tennis.
 From the fact that for all y_1, y_1 will go running we can infer that Jennifer is running. From the fact that Linda is playing tennis if and only if Jennifer is running we can infer that if Jennifer goes running, then Linda is playing tennis. Finally, from the fact that if Jennifer goes running, then Linda is playing tennis, and that Jennifer is running we can infer that Linda is playing tennis. Therefore, the answer is yes.