There is a pool, water pipe A is filled in 35 minutes alone, and water pipe B is filled in (1/5) hour alone, if A and B are filled with water at the same time, how long will it take to fill the pool?
有一个水池，甲水管单独35分钟注满，乙水管单独(1/5)小时注满，试求甲乙同时注水的话，多少分钟注满水池？
<gadget id="calculator">1 / 35</gadget>
<output>1/35 = around 0.028571</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/35) + (1/12)</gadget>
<output>47/420 = around 0.111905</output>

<gadget id="calculator">1 / (47/420)</gadget>
<output>420/47 = around 8.93617</output>

<result>420/47 = around 8.93617</result>