There are currently 8 kilograms of salt water with a concentration of 10%. If you want to obtain salt water with a concentration of 20%, please come up with an appropriate solution.
现有浓度为10%的盐水8千克，要想得到浓度为20%的盐水，请你想出恰当的方法解决．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">8 * (9/10)</gadget>
<output>36/5 = around 7.2</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">(36/5) / (4/5)</gadget>
<output>9</output>

<gadget id="calculator">9 - 8</gadget>
<output>1</output>

<result>1</result>