There is a glass of wine with an alcohol content of 45%. If 16 grams of water is added, the alcohol content becomes 25%. How many grams of alcohol are there in this glass of wine?
有一杯酒，食用酒精含量为45%，若添加16克水，酒精含量就变为25%，这杯酒中原来有食用酒精多少克？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">16 * (1/4)</gadget>
<output>4</output>

<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">(9/20) - (1/4)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">4 / (1/5)</gadget>
<output>20</output>

<gadget id="calculator">20 * (9/20)</gadget>
<output>9</output>

<result>9</result>