A, B and C jointly build a house, and one-third of the work is completed in 2 days, and then A rests for 6 days. B rested for 2 days, but C did not rest. It is known that the work efficiency of A is twice that of B, and the work efficiency of B is twice that of C, so how many days did it take to decorate this house from start to finish?
甲乙丙共同修建一套房子，2天完成了全部工作的三分之一，然后甲休息了6天．乙休息了2天，丙没有休息．已知甲的工作效率是乙的2倍，乙的工作效率是丙的2倍，那么装修这套房子从开始到完成共用了多少天？
<gadget id="calculator">1 + 2 + 4</gadget>
<output>7</output>

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

<gadget id="calculator">2 / (1/3) / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">7 * (6/7)</gadget>
<output>6</output>

<gadget id="calculator">4 * 7 * (6/7)</gadget>
<output>24</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">24 + 4</gadget>
<output>28</output>

<gadget id="calculator">28 / 7</gadget>
<output>4</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<result>10</result>