There is sugar water in a certain container, the teacher asked Xiaoqiang to pour 800 grams of 5% sugar water to make 20% sugar water, but Xiaoqiang poured 800 grams of water by mistake. Pour 400 grams of sugar water into the container, and you can get 20% sugar water. What are the concentrations of the three sugar waters?
某容器中装有糖水，老师让小强倒入5%的糖水800克，以配成20%的糖水，但小强却错误的倒入了800克水，老师发现后说不要紧，你再将第三种糖水400克倒入容器中，你就可以得到20%的糖水了．请问三种糖水的浓度是多少？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">400 * (1/5)</gadget>
<output>80</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">800 * (1/20)</gadget>
<output>40</output>

<gadget id="calculator">80 + 40</gadget>
<output>120</output>

<gadget id="calculator">120 / 400</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>