There are two water injection pipes, A and B, on the water tank. If pipe A is opened alone, the whole tank can be filled in 20 minutes. Now the two pipes are injected with water at the same time for 10 minutes, and the water tank is filled (4/5). If pipe B is opened alone, how much will it take Fill the tank in minutes?
水箱上有甲、乙两个注水管，单开甲管，20分钟可以注满全箱，现在两管同时注水10分钟，注满水箱的(4/5)，如果单开乙管，需要多少分钟注满水箱？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) / 10</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(2/25) - (1/20)</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">1 / (3/100)</gadget>
<output>100/3 = around 33.333333</output>

<result>100/3 = around 33.333333</result>