There are three numbers A, B, and C, A: B = 1: 2, B: C = 2: 3, if the number A is 6, what is the average of these three numbers?
甲、乙、丙三个数，甲：乙=1：2，乙：丙=2：3，如果甲数是6，那么这三个数的平均数是多少．
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<gadget id="calculator">6 + 12 + 18</gadget>
<output>36</output>

<gadget id="calculator">36 / 3</gadget>
<output>12</output>

<result>12</result>