A pool has two faucets A and B. If A and B are turned on at the same time, it takes 30 minutes to fill the pool. Now A and B are turned on at the same time for 10 minutes, A is turned off, and B continues to fill water for 80 minutes, and the pool can also be filled. Then turn on faucet B alone to fill water, how many minutes will it take to fill the pool.
某水池有A，B两个水龙头．如果A，B同时打开需要30分钟可将水池注满．现在A和B同时打开10分钟后，将A关闭，由B继续注水80分钟，也可将水池注满．那么单独打开B龙头注水，需要多少分钟才可将水池注满．
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/30) * 10</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) / 80</gadget>
<output>1/120 = around 0.008333</output>

<gadget id="calculator">1 / (1/120)</gadget>
<output>120</output>

<result>120</result>