There are 500 grams of salt water with a concentration of 3.2%, how many grams of water need to be evaporated in order to turn it into salt water with a concentration of 8%.
有浓度为3.2%的食盐水500克，为了把它变成浓度是8%的食盐水，需要使它蒸发掉多少克的水．
<gadget id="calculator">3.2 / 100</gadget>
<output>0.032</output>

<gadget id="calculator">8 / 100</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">0.032 / (2/25)</gadget>
<output>0.4</output>

<gadget id="calculator">500 * 0.4</gadget>
<output>200</output>

<gadget id="calculator">500 - 200</gadget>
<output>300</output>

<result>300</result>