A tank has two outlet pipes A and B. If pipe A is opened only, the water in the pool can be drained in (1/2) hour; when pipe B is opened only, the water in the pool can be drained in (1/3) hour. If the two pipes are opened together, how many hours can the full pool of water be drained?
一个水池装有甲、乙两个出水管．单开甲管，(1/2)小时可以把满池水放完；单开乙管，(1/3)小时可以把满池水放完．如果两管齐开，多少小时可以把满池水放完？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>