To build a road, it takes 20 days for A to repair alone, and 30 days for B to complete it alone. Now, after a few days of joint repair by A and B, team B is called out. It took 18 days to complete the road. How many days did it take for team B to repair it? ?
修一条路，甲独修要20天，乙独修要30天完成，现由甲乙两队合修若干天后，乙队调出，修完这条路共用了18天，求乙队修了多少天？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 18</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/10) / (1/30)</gadget>
<output>3</output>

<result>3</result>