How many grams of salt can be added to 100 g of brine with a concentration of 8% to obtain brine with a concentration of 20%.
向浓度为8%，质量为100克的盐水中加多少克盐，才能得到浓度为20%的盐水．
<gadget id="calculator">8 / 100</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">1 - (2/25)</gadget>
<output>23/25 = around 0.92</output>

<gadget id="calculator">100 * (23/25)</gadget>
<output>92</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">92 / (4/5)</gadget>
<output>115</output>

<gadget id="calculator">115 - 100</gadget>
<output>15</output>

<result>15</result>