There is a highway that requires 20 days for team A to repair alone, 15 days for team B to repair alone, and 12 days for team C to repair alone. Now let the three teams jointly repair it, but the middle team A withdraws to another construction site, and the result is used It took 6 days to complete the repair of this road. After Team A withdrew, how many days did it take Team B and Team C to jointly repair it?
有一条公路，甲队独修需20天，乙队独修需15天，丙除独修需12天，现在让三个队合修，但中间甲队撤出去到另外工地，结果用了6天才把这条公路修完，当甲队撤出后，乙、丙两队又共同合修了多少天才完成？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/20) + (1/15) + (1/12)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 6</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) - 1</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / (1/20)</gadget>
<output>4</output>

<result>4</result>