A cistern has an inlet pipe and an outlet pipe. With only one outlet pipe open, the pool full of water can be drained within 8 hours; with one water inlet pipe open within two hours, (1/3) of the pool water can be filled. How many hours can the empty tank be filled with two pipes now?
一个蓄水池安装了一个进水管和一个出水管．单开出水管，8小时可将满池水放完；单开进水管2小时可注入(1/3)池水．现两管齐开，多少小时可将空池注满？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2 / (1/3)</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/6) - (1/8)</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">1 / (1/24)</gadget>
<output>24</output>

<result>24</result>