For a job, A's work efficiency is the sum of B and C's work efficiency, and B's work efficiency is the sum of A and C's (1/5). If the three can complete it in one day, how many days will it take for B to complete it alone?
一件工作，甲的工作效率是乙丙工作效率之和，乙的工作效率是甲丙之和的(1/5)．如果三人合作1天就可以完成，那么乙单独完成需要多少天．
<gadget id="calculator">1 / 1</gadget>
<output>1</output>

<gadget id="calculator">1 / 1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 * (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 * (5/6)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) - (1/2)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

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

<result>6</result>