Given 200 grams of sugar water with a concentration of 20%, how many grams of water should be added to obtain sugar water with a concentration of 16%.
现有浓度为20%的糖水200克，要得到浓度为16%的糖水，需加水多少克．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">16 / 100</gadget>
<output>4/25 = around 0.16</output>

<gadget id="calculator">(1/5) / (4/25)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">200 * (5/4)</gadget>
<output>250</output>

<gadget id="calculator">250 - 200</gadget>
<output>50</output>

<result>50</result>