Final answer:
The state of the other transfer valve when one tank is low depends on the system's design, which may either close to prevent loss from the low-level tank or open to balance levels between tanks.
Step-by-step explanation:
When addressing the scenario where only one inner tank reaches a low level, the state of the other transfer valve will depend on the control system in place for managing the flow. Usually, in a system designed to maintain balance, if one tank's level is low, the transfer valve associated with the other tank might close to prevent fluid from moving away from the low-level tank, or it may open to allow fluid to balance between tanks, depending on whether the system aims to equalize levels or maintain a certain operating condition.
In systems where flow-through is used, where a ballast tank is flushed by drawing water in through a lower valve and out through an upper opening, the objective is often to maintain balance and stability within the vessel or structure. Similarly, in gas transfer cases, when a valve is opened between a flask with gas and a second flask containing a vacuum, the gas spontaneously becomes evenly distributed between the flasks.
Ultimately, the response of the other transfer valve will depend on the specific requirements of the system it's a part of, such as maintaining level, pressure, or flow rates.