A project can be completed by team A alone in 15 days, by team B in 10 days and by team C in 12 days. Now teams A, B and C are working together on this project. During the working process, team A rested for half a day, team C rested for 2 days, and team B did not rest. Find out how many days it took to complete the project.
一项工程，甲队单独做要15天完成，乙队单独工作要10天完成，丙队单独做要12天完成．现在甲、乙、丙三队合做这项工程．在工作过程中甲队休息了半天，丙队休息了2天，乙队没有休息．求完成这项工程前后一共用了多少天．
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/15) * 0.5</gadget>
<output>0.033333</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 2</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">0.033333 + (1/6) + 1</gadget>
<output>1.2</output>

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

<gadget id="calculator">(1/15) + (1/10) + (1/12)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1.2 / (1/4)</gadget>
<output>4.8</output>

<result>4.8</result>