Consider the following premises. For all x_12, x_12 is a cashier if and only if x_12 will read a book. For all x_12, x_12 will read a book. For all x_12, if x_12 cooks, then x_12 is taking a plane. For all x_12, if x_12 were a cashier, then x_12 is cooking. Can we infer the following from them? For all x_12, x_12 will take a plane.
 From the fact that for all x_12, x_12 is a cashier if and only if x_12 will read a book we can infer that for all x_12, if x_12 reads a book, then x_12 is a cashier. From the fact that for all x_12, if x_12 reads a book, then x_12 is a cashier, and that for all x_12, if x_12 were a cashier, then x_12 is cooking we can infer that for all x_12, if x_12 reads a book, then x_12 is cooking. From the fact that for all x_12, if x_12 reads a book, then x_12 is cooking, and that for all x_12, if x_12 cooks, then x_12 is taking a plane we can infer that for all x_12, if x_12 reads a book, then x_12 is taking a plane. Finally, from the fact that for all x_12, if x_12 reads a book, then x_12 is taking a plane, and that for all x_12, x_12 will read a book we can infer that for all x_12, x_12 will take a plane. Therefore, the answer is yes.