A project can be completed by A alone in 10 days and by B in 15 days. After A and B cooperate for 2 days, how many days will it take for B to complete the remaining project alone?
一件工程，甲单独做10天完成，乙单独做15天完成．甲乙合作2天后，剩下的工程由乙单独完成需要多少天？
<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">(1/6) * 2</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) / (1/15)</gadget>
<output>10</output>

<result>10</result>