There are three bottles of alcohol solution with the same weight, and the weight ratios of alcohol and water contained in the bottles are 3:2, 2:3 and 4:1 respectively. What is the concentration of the alcoholic solution obtained when three bottles of alcoholic solution are mixed?
有三瓶重量相同的酒精溶液，瓶中所含酒精与水的重量比分别是3：2、2：3和4：1．当把三瓶酒精溶液混合时，得到的酒精溶液浓度为多少．
<gadget id="calculator">3 + 2 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">9 / 15</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>