The average of the four numbers A, B, C, and D is 38, the average of A and B is 42, and the average of B, C, and D is 36. What is the number of B?
甲乙丙丁四个数的平均数是38，甲与乙的平均数是42，乙丙丁的平均数是36，求乙数是多少？
<gadget id="calculator">42 * 2</gadget>
<output>84</output>

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

<gadget id="calculator">84 + 108</gadget>
<output>192</output>

<gadget id="calculator">38 * 4</gadget>
<output>152</output>

<gadget id="calculator">192 - 152</gadget>
<output>40</output>

<result>40</result>