Scientific research has found that to treat cotton bollworms, 20ml of pesticides and 40,000ml of water are needed to prepare a liquid solution. How many milliliters of water should be added to the existing 50ml of pesticides? (column ratio calculation)
科学研究发现，治棉花棉铃虫需用20ml农药加40000ml水配制药液，现有50ml农药，要加多少毫升水？(列比例式计算)
<gadget id="calculator">20 / 40_000</gadget>
<output>1/2_000 = around 0.0005</output>

<gadget id="calculator">50 / (1/2_000)</gadget>
<output>100_000</output>

<result>100_000</result>