If you mix 70 grams of type A alcohol with 30 grams of type B alcohol, the concentration is 50%, if you mix the same amount of type A alcohol with type B alcohol, then the concentration is 56%, if you take 30 grams of type A alcohol and 70 What is the concentration after mixing gram of B alcohol?
如果取70克甲种酒精和30克乙种酒精混合，那么浓度为50%，如果取等量的甲种酒精和乙种酒精混合，那么浓度为56%，如果取30克甲种酒精和70克乙种酒精混合，混合后的浓度是多少．
<gadget id="calculator">41 / 100</gadget>
<output>41/100 = around 0.41</output>

<gadget id="calculator">30 * (41/100)</gadget>
<output>123/10 = around 12.3</output>

<gadget id="calculator">71 / 100</gadget>
<output>71/100 = around 0.71</output>

<gadget id="calculator">70 * (71/100)</gadget>
<output>497/10 = around 49.7</output>

<gadget id="calculator">(123/10) + (497/10)</gadget>
<output>62</output>

<gadget id="calculator">30 + 70</gadget>
<output>100</output>

<gadget id="calculator">62 / 100</gadget>
<output>31/50 = around 0.62</output>

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

<gadget id="calculator">(31/50) * 1</gadget>
<output>31/50 = around 0.62</output>

<result>31/50 = around 0.62</result>