Mix 80 grams of 5% salt water and 20 grams of 8% salt water, pour out 10 grams of it, and add 10 grams of water. What is the concentration of the salt water now?
5%的盐水80克，8%的盐水20克混合在一起，倒掉其中10克，再加入10克水，现在盐水的浓度是多少．
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">80 * (1/20)</gadget>
<output>4</output>

<gadget id="calculator">8 / 100</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">20 * (2/25)</gadget>
<output>8/5 = around 1.6</output>

<gadget id="calculator">4 + (8/5)</gadget>
<output>28/5 = around 5.6</output>

<gadget id="calculator">80 + 20</gadget>
<output>100</output>

<gadget id="calculator">(28/5) / 100</gadget>
<output>7/125 = around 0.056</output>

<gadget id="calculator">10 * (7/125)</gadget>
<output>14/25 = around 0.56</output>

<gadget id="calculator">5.6 - (14/25)</gadget>
<output>5.04</output>

<gadget id="calculator">100 - 10</gadget>
<output>90</output>

<gadget id="calculator">90 + 10</gadget>
<output>100</output>

<gadget id="calculator">5.04 / 100</gadget>
<output>0.0504</output>

<result>0.0504</result>