The ratio of the three numbers A, B, and C is 1:2:3, and the average number is 30, what is C?
甲、乙、丙三个数的比是1：2：3，平均数是30，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 * 3 * (1/2)</gadget>
<output>45</output>

<result>45</result>