How many grams of salt are added to 285 grams of water so that the salt content of the brine reaches 5%.
在285克水中加人多少克盐，使得盐水的含盐率达到5%．
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 - (1/20)</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">285 / (19/20)</gadget>
<output>300</output>

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

<result>15</result>