The ergonomics ratio of Pingping and Xingxing is 2:3. It takes 30 days for Pingping to complete a task alone. How many days will it take for the two to complete the project together?
平平和行行两人工效比是2：3，平平单独完成一项任务要30天，两人合干这项工程多少天完成任务？
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(1/30) * (3/2)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/30) + (1/20)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / (1/12)</gadget>
<output>12</output>

<result>12</result>