What is the concentration of the alcohol solution obtained after mixing 200 grams of 60% alcohol solution with 300 grams of 30% alcohol solution?
浓度为60%的酒精溶液200克，与浓度为30%的酒精溶液300克混合后所得到的酒精溶液的浓度是多少．
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">200 * (3/5)</gadget>
<output>120</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">300 * (3/10)</gadget>
<output>90</output>

<gadget id="calculator">120 + 90</gadget>
<output>210</output>

<gadget id="calculator">200 + 300</gadget>
<output>500</output>

<gadget id="calculator">210 / 500</gadget>
<output>21/50 = around 0.42</output>

<result>21/50 = around 0.42</result>