For a task, the master and apprentice completed 1/5 of the entire task in 2 days, and then the master stopped working for 3 days for some reason, and then continued to cooperate with the apprentice. It is known that the ratio of work efficiency between the master and the apprentice is 2:1. How many days did it take to complete this task?
一项任务，师徒合作2天完成了全部任务的(1/5)，接着师傅因故停工3天，后继续与徒弟合作，已知师、徒二人工作效率的比是2：1，完成这一任务前后一共用了多少天？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) / 2</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/10) * (1/3) * 3</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/5) - (1/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">(7/10) / (1/10)</gadget>
<output>7</output>

<gadget id="calculator">7 + 2 + 3</gadget>
<output>12</output>

<result>12</result>