Last winter, farmers in Hongyu Township teamed up to repair a 20-kilometer-long weir ditch. Team A can complete it in 10 days, team B can complete it in 12 days, and team C can complete it in 15 days. In fact, after Team A has completed two days first, Team B and Team C will jointly repair the rest. How many days will it take to complete? (solution in different ways)
去年冬季，红玉乡的农民组队维修一条长20千米的堰沟．甲队独修10天能完成，乙队独修12天能完成，丙队独修15天能完成．实际甲队先修了两天后，剩下的由乙队和丙队合修，还要多少天才能完成？(用不同方法解)
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

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

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

<gadget id="calculator">(1/12) + (1/15)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(4/5) / (3/20)</gadget>
<output>16/3 = around 5.333333</output>

<result>16/3 = around 5.333333</result>