project is completed in 3 days alone, and B is completed in 15 days alone. After A and B cooperate for 2 days, how many days will B have to do the remaining work?
一项工程甲单独做3天完成了，乙单独做15天完成，甲乙合作2天后，余下的工作乙还要做几天？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(1/3) + (1/15)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) * 2</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / (1/15)</gadget>
<output>3</output>

<result>3</result>