If 20 grams of salt is used to make brine with a salt content of 5%, how many grams of water should be added?
用20克盐配制成含盐率5%的盐水，应加水多少克．
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">20 / (1/20)</gadget>
<output>400</output>

<gadget id="calculator">400 - 20</gadget>
<output>380</output>

<result>380</result>