The average of the two numbers A and B is 80, and the number C is 50. What is the average of these three numbers?
甲乙两个数的平均数是80，丙数是50，这三个数的平均数是多少．
<gadget id="calculator">80 * 2</gadget>
<output>160</output>

<gadget id="calculator">160 + 50</gadget>
<output>210</output>

<gadget id="calculator">210 / 3</gadget>
<output>70</output>

<result>70</result>