How many grams of salt should be dissolved in 60 grams of water to prepare salt water with a concentration of 25%.
配制浓度为25%的盐水，要用多少克盐溶入60克水中．
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(1/4) / (3/4)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">60 * (1/3)</gadget>
<output>20</output>

<result>20</result>