pool has an inlet pipe A and a drain pipe B. When the tank is empty, if both tubes A and B are opened at the same time, the pool can be filled in 10 hours; if tube A is opened for 4 hours and then closed, and tube B is opened for 2 hours, water can be filled to (3/5) of the pool. If there is already water (1/6) in the pool, then in the order of A and B, turn on each of them for 1 hour. How many hours will it take to fill the pool?
一水池有甲进水管和乙排水管各一根．空池时，若同时打开甲乙两管，10小时可将水池注满；如先打开甲管4小时后再关闭，此时打开乙管2小时，则可注水到水池的(3/5)．若水池中已有水(1/6)，那么按甲乙的顺序轮流各开1小时，要将水池注满需要多少小时？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 8</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (1/6) - (4/5)</gadget>
<output>1/30 = around 0.033333</output>

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

<gadget id="calculator">(1/30) / (1/5)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">8 + (1/6)</gadget>
<output>49/6 = around 8.166667</output>

<result>49/6 = around 8.166667</result>