It takes 80 tons of water to fill a pool. If pipe A is opened alone for 5 hours, it can discharge the full pool of water, and pipe B can put 24 tons of water in an hour. If the two pipes are opened together, how many hours can the empty tank be filled.
装满一个水池需要80吨水．甲管单独开5小时可把满池水放完，乙管每小时可放入24吨水．如果两管齐开，多少小时可把空池装满．
<gadget id="calculator">80 / 5</gadget>
<output>16</output>

<gadget id="calculator">16 + 24</gadget>
<output>40</output>

<gadget id="calculator">80 / 40</gadget>
<output>2</output>

<result>2</result>