A cuboid tank can hold 480 tons of water. The sink is equipped with a water inlet pipe and a drain pipe. Opening the water inlet pipe alone can fill the empty pool for 8 hours; opening the drain pipe alone can empty the full pool for 6 hours. How many hours will it take for both pipes to empty the full pool?
一个长方体的水槽可容水480吨．水槽装有一个进水管和一个排水管．单开进水管8小时可以把空池注满；单开排水管6小时可把满池水排空．两管齐开需多少小时把满池水排空？
<gadget id="calculator">480 / 6</gadget>
<output>80</output>

<gadget id="calculator">480 / 8</gadget>
<output>60</output>

<gadget id="calculator">80 - 60</gadget>
<output>20</output>

<gadget id="calculator">480 / 20</gadget>
<output>24</output>

<result>24</result>