There are four numbers a, b, c, and d, one of which is removed each time, and then the average of the remaining three numbers is calculated, and the four numbers of 28, 31, 35, and 38 are obtained respectively. , What is the average of the four numbers a, b, c, and d?
有a、b、c、d四个数，每次都去掉其中的一个数，然后再求其余三个数的平均数，这样计算了四次，分别得到28、31、35、38四个数，a、b、c、d四个数的平均数是多少．
<gadget id="calculator">28 * 3</gadget>
<output>84</output>

<gadget id="calculator">31 * 3</gadget>
<output>93</output>

<gadget id="calculator">35 * 3</gadget>
<output>105</output>

<gadget id="calculator">38 * 3</gadget>
<output>114</output>

<gadget id="calculator">84 + 93 + 105 + 114</gadget>
<output>396</output>

<gadget id="calculator">396 / 3</gadget>
<output>132</output>

<gadget id="calculator">132 / 4</gadget>
<output>33</output>

<result>33</result>