If 15 grams of salt is used to make brine with a salt content of 5%, how many grams of water should be added?
用15克盐配制成含盐率为5%的盐水，需加水多少克？
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">15 / (1/20)</gadget>
<output>300</output>

<gadget id="calculator">300 - 15</gadget>
<output>285</output>

<result>285</result>