There are four groups A, B, C, and D. The average number of people in groups A, B, C is 24, and the average number of people in groups B, C, and D is 26. If there are 25 people in group A, how many people are there in group D?
有甲乙丙丁四个小组，其中甲乙丙三个小组的平均人数是24人，乙丙丁三个小组的平均人数是26人，如果甲组有25人，那么丁组有多少人．
<gadget id="calculator">26 * 3</gadget>
<output>78</output>

<gadget id="calculator">24 * 3</gadget>
<output>72</output>

<gadget id="calculator">72 - 25</gadget>
<output>47</output>

<gadget id="calculator">78 - 47</gadget>
<output>31</output>

<result>31</result>