my country is one of the most water-scarce countries in the world, with per capita fresh water resources of 2,300 tons, only equivalent to 25% of the world's average. Xiaohua wants to invent a set of equipment for desalinating seawater, which can desalinate 29,900,000 tons of pure water per hour. Then, how many hours does this set of equipment need to operate to make my country's per capita fresh water resources reach the world's average level (calculated with a national population of 1.3 billion)
我国是世界最缺水的国家之一，人均淡水资源2300吨，仅相当于世界人均的25%．小华想发明一套使海水淡化的设备，每小时淡化出纯净水29900000吨．那么，要使我国人均淡水资源达到世界平均水平，这套设备要运转多少小时(全国人口以13亿计算)
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2_300 / (1/4)</gadget>
<output>9_200</output>

<gadget id="calculator">9_200 - 2_300</gadget>
<output>6_900</output>

<gadget id="calculator">1_300_000_000 / 29_900_000</gadget>
<output>1_000/23 = around 43.478261</output>

<gadget id="calculator">6_900 * (1_000/23)</gadget>
<output>300_000</output>

<result>300_000</result>