Consider the following premises. Thomas is a soldier if and only if Elisabeth is cooking. For all x_20, if x_20 were a janitor, then x_20 is a soldier. Thomas is a janitor if and only if Richard is drinking water. Can we infer the following from them? If Richard drinks water, then Elisabeth is cooking.
 From the fact that for all x_20, if x_20 were a janitor, then x_20 is a soldier we can infer that if Thomas were a janitor, then Thomas is a soldier. From the fact that Thomas is a janitor if and only if Richard is drinking water we can infer that if Richard drinks water, then Thomas is a janitor. From the fact that if Richard drinks water, then Thomas is a janitor, and that if Thomas were a janitor, then Thomas is a soldier we can infer that if Richard drinks water, then Thomas is a soldier. From the fact that Thomas is a soldier if and only if Elisabeth is cooking we can infer that if Thomas were a soldier, then Elisabeth is cooking. Finally, from the fact that if Richard drinks water, then Thomas is a soldier, and that if Thomas were a soldier, then Elisabeth is cooking we can infer that if Richard drinks water, then Elisabeth is cooking. Therefore, the answer is yes.