The average of the three numbers A, B, and C is 2.4, and the ratio of the three numbers A, B, and C is 2:1:3. What is the number of A?
甲、乙、丙三个数的平均数是2.4，甲、乙、丙三个数的比是2：1：3，则甲数是多少．
<gadget id="calculator">1 + 2 + 3</gadget>
<output>6</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2.4 * 3 * (1/3)</gadget>
<output>2.4</output>

<result>2.4</result>