A project can be completed by team A alone in 10 days, and team B alone can be completed in 30 days. Now the two teams are working together. During this period, team A rested for 2 days, and team B rested for 8 days (there is no such thing as two teams resting on the same day). Find out how many days it took from start to finish.
一项工程甲队单独做10完成，乙队单独做30天完成．现在两队合作，在这期间，甲队休息了2天，乙队休息了8天(不存在两队同一天休息)，求开始到完工共用了多少天的时间．
<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

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

<gadget id="calculator">2 + 8 + 1</gadget>
<output>11</output>

<result>11</result>