To build a canal, A alone can complete it in 3 days (1/5), and team B can complete it in 2 days alone (1/10). In this way, how many days will it take for teams A and B to cooperate?
修一条水渠，甲单独做3天可以完成(1/5)，乙队单独做2天可以完成(1/10)，照这样做，甲乙两队合作多少天完成？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / 3</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) / 2</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/15) + (1/20)</gadget>
<output>7/60 = around 0.116667</output>

<gadget id="calculator">1 / (7/60)</gadget>
<output>60/7 = around 8.571429</output>

<result>60/7 = around 8.571429</result>