It takes 20 days for team A to do a project alone, and 12 days for team B to do it alone. What percentage of the project can be completed in one day by the cooperation of two pairs?
一项工程，甲队单独做需要20天，乙队单独做需要12天，两对合作一天可以完成这项工程的几分之几？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

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

<gadget id="calculator">(1/20) + (1/12)</gadget>
<output>2/15 = around 0.133333</output>

<result>2/15 = around 0.133333</result>