There is a cube water tank with three outlet holes of the same size at the same height on one side. Use one water inlet pipe to fill the empty water tank. If all three water outlet holes are closed, it takes 1 hour to fill the water tank; if one water outlet hole is opened, it takes 1 hour and 5 minutes to fill the water tank; outlet hole, it takes 72 minutes to fill the water tank. So, if all three outlet holes are fully open, how many minutes will it take to fill the water tank?
有一个正方体水箱，在某一个侧面相同高度的地方有三个大小相同的出水孔．用一个进水管给空水箱灌水，若三个出水孔全关闭，则需要用1个小时将水箱灌满；若打开一个出水孔，则需要用1小时5分钟将水箱灌满；若打开两个出水孔，则需要用72分钟将水箱灌满．那么，若三个出水孔全打开，则需要用多少分钟才能将水箱灌满？
<gadget id="calculator">72 - 65</gadget>
<output>7</output>

<gadget id="calculator">7 * 5</gadget>
<output>35</output>

<gadget id="calculator">65 - 35</gadget>
<output>30</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">3 * (1/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">30 / (4/7)</gadget>
<output>105/2 = around 52.5</output>

<gadget id="calculator">30 + (105/2)</gadget>
<output>165/2 = around 82.5</output>

<result>165/2 = around 82.5</result>