Consider the following premises. There is at least one x_10 for which if x_10 sleeps, then x_10 is a cashier. For all x_10, x_10 will take a plane if and only if x_10 is rich. For all x_10, x_10 is not rich. For all x_10, x_10 is not a scientist or x_10 will sleep. For all x_10, x_10 is a scientist or x_10 will take a plane. Can we infer the following from them? There is at least one x_10 for which x_10 is a cashier.
 From the fact that for all x_10, x_10 will take a plane if and only if x_10 is rich, and that for all x_10, x_10 is not rich we can infer that for all x_10, x_10 will not take a plane. From the fact that for all x_10, x_10 is a scientist or x_10 will take a plane, and that for all x_10, x_10 is not a scientist or x_10 will sleep we can infer that for all x_10, x_10 will take a plane or x_10 will sleep. From the fact that for all x_10, x_10 will take a plane or x_10 will sleep, and that for all x_10, x_10 will not take a plane we can infer that for all x_10, x_10 will sleep. Finally, from the fact that there is at least one x_10 for which if x_10 sleeps, then x_10 is a cashier, and that for all x_10, x_10 will sleep we can infer that there is at least one x_10 for which x_10 is a cashier. Therefore, the answer is yes.