200 grams of a 20% brine, after adding some water, the salt content becomes 12.5%, how much water was added?
一种20%盐水200克，加了一些水后，含盐量成为12.5%，加了多少水？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">12.5 / 100</gadget>
<output>0.125</output>

<gadget id="calculator">(1/5) / 0.125</gadget>
<output>1.6</output>

<gadget id="calculator">200 * 1.6</gadget>
<output>320</output>

<gadget id="calculator">320 - 200</gadget>
<output>120</output>

<result>120</result>