Consider the following premises. For all y_3, y_3 will drink water or y_3 is bored. For all y_3, y_3 will not read a book. There is at least one y_3 for which y_3 will read a book if and only if y_3 will drink water. Can we infer the following from them? There is at least one y_3 for which y_3 is bored.
 From the fact that there is at least one y_3 for which y_3 will read a book if and only if y_3 will drink water, and that for all y_3, y_3 will not read a book we can infer that there is at least one y_3 for which y_3 will not drink water. Finally, from the fact that for all y_3, y_3 will drink water or y_3 is bored, and that there is at least one y_3 for which y_3 will not drink water we can infer that there is at least one y_3 for which y_3 is bored. Therefore, the answer is yes.