Consider the following premises. For all x_7, x_7 will drink water. For all x_7, x_7 is a sailor if and only if x_7 will play squash. For all x_7, x_7 is a sailor. Can we infer the following from them? For all x_7, x_7 will play squash and x_7 will drink water.
 From the fact that for all x_7, x_7 is a sailor if and only if x_7 will play squash we can infer that for all x_7, if x_7 were a sailor, then x_7 is playing squash. From the fact that for all x_7, if x_7 were a sailor, then x_7 is playing squash, and that for all x_7, x_7 is a sailor we can infer that for all x_7, x_7 will play squash. Finally, from the fact that for all x_7, x_7 will play squash, and that for all x_7, x_7 will drink water we can infer that for all x_7, x_7 will play squash and x_7 will drink water. Therefore, the answer is yes.