There are three numbers A, B, and C. The average of the two numbers A and B is 33, the average of the two numbers B and C is 35, and the average of the two numbers A and C is 40. Find the average of the three numbers.
甲、乙、丙三个数，甲乙两数的平均数是33，乙丙两数的平均数是35，甲丙两数的平均数是40，求三个数的平均数．
<gadget id="calculator">33 * 2</gadget>
<output>66</output>

<gadget id="calculator">35 * 2</gadget>
<output>70</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">66 + 70 + 80</gadget>
<output>216</output>

<gadget id="calculator">216 / 2</gadget>
<output>108</output>

<gadget id="calculator">108 / 3</gadget>
<output>36</output>

<result>36</result>