A project can be completed by team A in 15 days alone and team B in 10 days alone. After the two teams cooperate for 3 days, the rest will be done by team A. How many days will it take for team A to finish?
一项工程，甲队独做15天完成，乙队独做10天完成．两队合作3天后，剩下的由甲队完成，甲队还要多少天才能完成？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

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

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

<gadget id="calculator">(1/6) * 3</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) / (1/15)</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>