Xin'anjiang Reservoir is going to discharge flood, opening A mouth can go below the safety line for 8 hours, and opening B mouth can go below the safety line for 10 hours. Now open two openings at the same time, how many hours can you get below the safety line?
新安江水库要泄洪，打开甲口子8小时可以到安全线以下，打开乙口子10小时可以到安全线以下．现在同时打开两个口子，多少小时可以到安全线以下？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

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

<gadget id="calculator">(1/8) + (1/10)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">1 / (9/40)</gadget>
<output>40/9 = around 4.444444</output>

<result>40/9 = around 4.444444</result>