The average of three numbers is 86. The first number is 92, which is twice the second number. What is the third number?
三个数的平均数是86，其中第一个数是92，是第二个数的2倍，第三个数是多少．
<gadget id="calculator">86 * 3</gadget>
<output>258</output>

<gadget id="calculator">92 / 2</gadget>
<output>46</output>

<gadget id="calculator">258 - 92 - 46</gadget>
<output>120</output>

<result>120</result>