project can be completed by Team A alone in 30 days, and by Team B in 20 days. How much can the two teams complete in 5 days?
一项工程，由甲队单独做需30天完成，由乙队单独做需20天完成，两队合作5天可以完成这项工程的多少．
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / 20</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">(1/12) * 5</gadget>
<output>5/12 = around 0.416667</output>

<result>5/12 = around 0.416667</result>