Consider the following premises. For all x, if x plays tennis, then x is listening to a song. For all x, if x listens to a song, then x is playing squash. For all x, x will play squash if and only if x will play tennis. Can we infer the following from them? For all x, if x plays squash, then x is playing tennis.
 From the fact that for all x, if x plays tennis, then x is listening to a song, and that for all x, if x listens to a song, then x is playing squash we can infer that for all x, if x plays tennis, then x is playing squash. Finally, from the fact that for all x, x will play squash if and only if x will play tennis we can infer that for all x, if x plays squash, then x is playing tennis. Therefore, the answer is yes.