There are 120 grams of sugar water with a sugar content of 10%. To make the sugar water 30%, how many grams of water need to be evaporated
有糖水120克，含糖率为10%，要使糖水的含糖率为30%，需要蒸发掉水多少克
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/10) / (3/10)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">120 * (1/3)</gadget>
<output>40</output>

<gadget id="calculator">120 - 40</gadget>
<output>80</output>

<result>80</result>