Consider the following premises. There is at least one x for which x is a scientist if and only if x will read a book. For all x, x will read a book or x is not a writer. For all x, if x were a scientist, then x is a writer. Can we infer the following from them? For all x, if is not true that x is a writer if and only if x will read a book.
 From the fact that there is at least one x for which x is a scientist if and only if x will read a book we can infer that there is at least one x for which if x reads a book, then x is a scientist. From the fact that for all x, x will read a book or x is not a writer we can infer that for all x, if x were a writer, then x is reading a book. From the fact that there is at least one x for which if x reads a book, then x is a scientist, and that for all x, if x were a scientist, then x is a writer we can infer that there is at least one x for which if x reads a book, then x is a writer. Finally, from the fact that for all x, if x were a writer, then x is reading a book, and that there is at least one x for which if x reads a book, then x is a writer we can infer that there is at least one x for which x is a writer if and only if x will read a book, which contradicts that For all x, if is not true that x is a writer if and only if x will read a book. Therefore, the answer is no.