Consider the following premises. Linda is not playing squash. For all x_20, x_20 will play tennis if and only if x_20 will play squash. If John listens to a song, then Linda is playing tennis. Can we infer the following from them? John is listening to a song.
 From the fact that for all x_20, x_20 will play tennis if and only if x_20 will play squash we can infer that Linda is playing tennis if and only if Linda is playing squash. From the fact that Linda is playing tennis if and only if Linda is playing squash, and that Linda is not playing squash we can infer that Linda is not playing tennis. Finally, from the fact that if John listens to a song, then Linda is playing tennis, and that Linda is not playing tennis we can infer that John is not listening to a song, which contradicts that John is listening to a song. Therefore, the answer is no.