Consider the following premises. For all x_9, if x_9 were rich, then x_9 is an office clerk. For all x_9, x_9 is an office clerk or x_9 is not rich. For all x_9, if x_9 were an office clerk, then x_9 is rich. Can we infer the following from them? For all x_9, x_9 is an office clerk if and only if x_9 is rich.
 From the fact that for all x_9, if x_9 were rich, then x_9 is an office clerk, and that for all x_9, if x_9 were an office clerk, then x_9 is rich we can infer that for all x_9, x_9 is rich if and only if x_9 is an office clerk. From the fact that for all x_9, x_9 is rich if and only if x_9 is an office clerk we can infer that for all x_9, if x_9 were an office clerk, then x_9 is rich. From the fact that for all x_9, x_9 is an office clerk or x_9 is not rich we can infer that for all x_9, if x_9 were rich, then x_9 is an office clerk. Finally, from the fact that for all x_9, if x_9 were an office clerk, then x_9 is rich, and that for all x_9, if x_9 were rich, then x_9 is an office clerk we can infer that for all x_9, x_9 is an office clerk if and only if x_9 is rich. Therefore, the answer is yes.