The average of the three numbers A, B, and C is 30, A: B: C = 1: 2: 3, then what is C
甲、乙、丙三个数的平均数是30，甲：乙：丙=1：2：3，则丙是多少
<gadget id="calculator">1 + 2 + 3</gadget>
<output>6</output>

<gadget id="calculator">3 / 6</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 * (1/2)</gadget>
<output>15</output>

<gadget id="calculator">15 * 3</gadget>
<output>45</output>

<result>45</result>