The earth's fresh water resources only account for (1/40) of the world's water resources, and only about (1/100) of the fresh water can be directly used by humans, of which China accounts for (1/15). What percentage of the world's water resources does China's directly usable freshwater resources account for?
地球的淡水资源仅占世界水资源的(1/40)，只有约(1/100)的淡水可以为人类直接利用，其中中国占(1/15)．中国可直接利用的淡水资源占世界水资源的几分之几？
<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">1 / 100</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/40) * (1/100) * (1/15)</gadget>
<output>1/60_000 = around 0.000017</output>

<result>1/60_000 = around 0.000017</result>