For three alcohol solutions of the same weight, the ratio of alcohol to water is 2:1, 3:1, 4:1 respectively. Mix these three alcohol solutions, what is the concentration of the mixed alcohol solution
三份重量相同的酒精溶液，酒精与水的比分别为2：1、3：1、4：1．把这三份酒精溶液混合，混合后的酒精溶液的浓度是多少
<gadget id="calculator">74 / 100</gadget>
<output>37/50 = around 0.74</output>

<result>37/50 = around 0.74</result>