How many grams of water need to be added to turn 600 grams of salt water with 15% salt into salt water with 10% salt?
将含盐15%的600克盐水变成含盐10%的盐水，需要添加多少克水．
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(3/20) / (1/10)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">600 * (3/2)</gadget>
<output>900</output>

<gadget id="calculator">900 - 600</gadget>
<output>300</output>

<result>300</result>