To turn 120 grams of salt water with a salt content of 15% into salt water with a salt content of 25%, how many grams of water must be evaporated?
把含盐15%的120克盐水，变成含盐25%的盐水，要蒸发多少克水？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(3/20) / (1/4)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">120 * (3/5)</gadget>
<output>72</output>

<gadget id="calculator">120 - 72</gadget>
<output>48</output>

<result>48</result>