Consider the following premises. For all x_10, if x_10 were sad, then x_10 is climbing a mountain. For all x_10, if x_10 climbs a mountain, then x_10 is reading a book. There is at least one x_10 for which if x_10 reads a book, then x_10 is sad. For all x_10, x_10 will work if and only if x_10 will climb a mountain. For all x_10, x_10 will not work. Can we infer the following from them? There is at least one x_10 for which x_10 will not read a book.
 From the fact that for all x_10, x_10 will work if and only if x_10 will climb a mountain, and that for all x_10, x_10 will not work we can infer that for all x_10, x_10 will not climb a mountain. From the fact that there is at least one x_10 for which if x_10 reads a book, then x_10 is sad, and that for all x_10, if x_10 were sad, then x_10 is climbing a mountain we can infer that there is at least one x_10 for which if x_10 reads a book, then x_10 is climbing a mountain. From the fact that for all x_10, if x_10 climbs a mountain, then x_10 is reading a book, and that there is at least one x_10 for which if x_10 reads a book, then x_10 is climbing a mountain we can infer that there is at least one x_10 for which x_10 will climb a mountain if and only if x_10 will read a book. Finally, from the fact that there is at least one x_10 for which x_10 will climb a mountain if and only if x_10 will read a book, and that for all x_10, x_10 will not climb a mountain we can infer that there is at least one x_10 for which x_10 will not read a book. Therefore, the answer is yes.