What is the concentration of brine obtained by mixing 20L of 10% brine with 10L of 4% brine
将20L浓度为10%的盐水与10L浓度为4%的盐水混合，得到的盐水的浓度为多少
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">20 * (1/10)</gadget>
<output>2</output>

<gadget id="calculator">4 / 100</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">10 * (1/25)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 + (2/5)</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<gadget id="calculator">(12/5) / 30</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(2/25) * 1</gadget>
<output>2/25 = around 0.08</output>

<result>2/25 = around 0.08</result>