A cup of sugar water, the ratio of sugar to water is 1:20, add 2 grams of sugar, then the ratio of sugar to water is 1:11. How many grams of water is in this cup of sugar water?
一杯糖水，糖和水的比是1：20，在加入2克糖，这时糖和水的比是1：11．这杯糖水中原来有水多少克？
<gadget id="calculator">1 / 11</gadget>
<output>1/11 = around 0.090909</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/11) - (1/20)</gadget>
<output>9/220 = around 0.040909</output>

<gadget id="calculator">2 / (9/220)</gadget>
<output>440/9 = around 48.888889</output>

<result>440/9 = around 48.888889</result>