A project can be completed by team A alone in 10 days and by team B in 15 days alone. How many days will it take for teams A and B to do the whole process (1/2) together?
一项工程，甲队单独做10天完成，乙队单独做15天完成．甲、乙两队合做全程的(1/2)，需几天？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/2) / (1/6)</gadget>
<output>3</output>

<result>3</result>