Consider the following premises. For all x_5, if x_5 plays squash, then x_5 is drinking water. For all x_5, if x_5 plays squash, then x_5 is drinking water. For all x_5, if x_5 drinks water, then x_5 is playing squash. Can we infer the following from them? For all x_5, x_5 will play squash if and only if x_5 will drink water.
 From the fact that for all x_5, if x_5 drinks water, then x_5 is playing squash, and that for all x_5, if x_5 plays squash, then x_5 is drinking water we can infer that for all x_5, x_5 will drink water if and only if x_5 will play squash. From the fact that for all x_5, x_5 will drink water if and only if x_5 will play squash we can infer that for all x_5, if x_5 drinks water, then x_5 is playing squash. Finally, from the fact that for all x_5, if x_5 plays squash, then x_5 is drinking water, and that for all x_5, if x_5 drinks water, then x_5 is playing squash we can infer that for all x_5, x_5 will play squash if and only if x_5 will drink water. Therefore, the answer is yes.