The average of the three numbers A, B, and C is 5.2, and the average of the two numbers A and B is 6.2. What is the number of C?
甲、乙、丙三个数的平均数是5.2，甲、乙两个数的平均数是6.2，丙数是多少．
<gadget id="calculator">5.2 * 3</gadget>
<output>15.6</output>

<gadget id="calculator">6.2 * 2</gadget>
<output>12.4</output>

<gadget id="calculator">15.6 - 12.4</gadget>
<output>3.2</output>

<result>3.2</result>